diff --git a/December-01/C++_AminulIslam254.cpp b/December-01/C++_AminulIslam254.cpp
new file mode 100644
index 0000000..96b3979
--- /dev/null
+++ b/December-01/C++_AminulIslam254.cpp
@@ -0,0 +1,49 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+typedef long long ll;
+
+ll fun1(vector<string> s)
+{
+    ll i,count1=0;
+    char j;
+    ll n=s.size();
+    ll a[26]={0};
+    for(i=0;i<n;i++)
+    {
+        string temp1=s[i];
+        for(j='a';j<='z';j++)
+        {
+            if(temp1.find(j)!=string::npos)
+            {
+                a[j-'a']++;
+            }
+        }
+    }
+    for(i=0;i<26;i++)
+    {
+        if(a[i]==n)
+        {
+            count1++;
+        }
+    }
+    return count1;
+}
+
+int main()
+{
+    vector<string> s;
+    int i,n;
+    cout<< "Enter the no of elements"<<endl;cin>>n;
+    cout<< "Enter the elements"<<endl;
+    for(i=0;i<n;i++)
+    {
+        string temp1;
+        cin>>temp1;
+        s.push_back(temp1);
+    }
+    cout<<fun1(s)<<endl;
+
+    return 0;
+}
diff --git a/December-02/C++_AminulIslam254.cpp b/December-02/C++_AminulIslam254.cpp
new file mode 100644
index 0000000..5485dc8
--- /dev/null
+++ b/December-02/C++_AminulIslam254.cpp
@@ -0,0 +1,46 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+typedef long long ll;
+
+bool fun1(ll n)
+{
+    unordered_set<ll> s1;
+    while(1)
+    {
+        ll temp1=0;
+        while(n)
+        {
+            temp1+=((n%10)*(n%10));
+            n/=10;
+        }
+        if(temp1==1)
+        {
+            return true;
+        }
+        if(s1.count(temp1))
+        {
+            return false;
+        }
+        s1.insert(temp1);
+        n=temp1;
+    }
+}
+
+int main()
+{
+    ll n;
+    cout<< "Enter the element"<<endl;
+    cin>>n;
+    if(fun1(n))
+    {
+        cout<< "YES"<<endl;
+    }
+    else
+    {
+        cout<< "NO" <<endl;
+    }
+
+    return 0;
+}
diff --git a/December-03/C++_AminulIslam254.cpp b/December-03/C++_AminulIslam254.cpp
new file mode 100644
index 0000000..75d6b56
--- /dev/null
+++ b/December-03/C++_AminulIslam254.cpp
@@ -0,0 +1,66 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+typedef long long ll;
+
+
+int fun1(vector<vector<char>> a,string s,string name,ll i,ll j,ll r,ll c)
+{
+    if(s.length()>name.length())
+    {
+        return 0;
+    }
+    if(i>=r)
+    {
+        return 0;
+    }
+    if(j>=c)
+    {
+        return 0;
+    }
+    if(s==name)
+    {
+        return 1;
+    }
+    int m1=(fun1(a,s+a[i][j],name,i,j+1,r,c));
+    int m2=(fun1(a,s,name,i+1,j,r,c));
+    int m3=(fun1(a,s,name,i,j+1,r,c));
+    int m4=(fun1(a,s+a[i][j],name,i+1,j,r,c));
+    return m1+m2+m3+m4;
+}
+
+int main()
+{
+    ll r,c;
+    cout<< "Enter the no of rows"<<endl;
+    cin>>r;
+    cout<< "Enter the no of coloumns"<<endl;
+    cin>>c;
+    vector<vector<char>>a;
+    ll i,j;
+    cout<< "Enter elements"<<endl;
+    for(i=0;i<r;i++)
+    {
+        vector<char>temp1;
+        for(j=0;j<c;j++)
+        {
+            char c; cin>>c;
+            temp1.push_back(c);
+        }
+        a.push_back(temp1);
+    }
+    string s="";
+    string name;
+    cout<< "Enter name"<<endl;
+    cin>>name;
+    if(fun1(a,s,name,0,0,r,c))
+    {
+        cout<< "YES"<<endl;
+    }
+    else
+    {
+        cout<< "NO" <<endl;
+    }
+    return 0;
+}
diff --git a/December-05/C++_AminulIslam254.cpp b/December-05/C++_AminulIslam254.cpp
new file mode 100644
index 0000000..6fe2bf8
--- /dev/null
+++ b/December-05/C++_AminulIslam254.cpp
@@ -0,0 +1,68 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+typedef long long ll;
+
+int main()
+{
+    ll n1,n2,i;
+    cout<< "Enter the no of customers"<<endl;
+    cin>>n1;
+    cout<< "Enter the no of biscuits"<<endl;
+    cin>>n2;
+    queue<ll> customers,biscuits;
+    cout<< "Enter the customers preferances"<<endl;
+    for(i=0;i<n1;i++)
+    {
+        ll var;cin>>var;
+        customers.push(var);
+    }
+    cout<< "Enter the biscuits types"<<endl;
+    for(i=0;i<n2;i++)
+    {
+        ll var;cin>>var;
+        biscuits.push(var);
+    }
+
+    ll ans=0;
+    while(!customers.empty())
+    {
+        if(customers.front()==biscuits.front())
+        {
+            customers.pop();
+            biscuits.pop();
+        }
+        else
+        {
+            queue<ll> temp1=customers;
+            bool flag=false;
+            while(!temp1.empty())
+            {
+                if(temp1.front()==biscuits.front())
+                {
+                    flag=true;
+                    break;
+                }
+                temp1.pop();
+            }
+            if(flag)
+            {
+                customers.push(customers.front());
+                customers.pop();
+            }
+            else
+            {
+                break;
+            }
+
+        }
+    }
+    if(!customers.empty())
+    {
+        ans+=customers.size();
+    }
+    cout<<ans<<endl;
+
+    return 0;
+}
diff --git a/December-06/C++_AminulIslam254.cpp b/December-06/C++_AminulIslam254.cpp
new file mode 100644
index 0000000..bc4acd7
--- /dev/null
+++ b/December-06/C++_AminulIslam254.cpp
@@ -0,0 +1,87 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+typedef long long ll;
+
+int main()
+{
+    string s; cin>>s;
+    vector<ll> posu;
+    vector<ll> post;
+    ll i;
+    for(i=0;i<s.length();i++)
+    {
+        if(s[i]=='U')
+        {
+            posu.push_back(i);
+        }
+        else
+        {
+            post.push_back(i);
+        }
+    }
+    ll ans=0,j;
+    if(post.size()<=posu.size())
+    {
+        ll ind=posu[0];
+        bool flag=false;
+        for(i=0;i<posu.size();i++)
+        {
+            if(ind!=posu[i])
+            {
+                ll back1=posu.back();
+                swap(s[ind],s[back1]);
+                post.push_back(back1);
+                sort(post.begin(),post.end());
+                for(j=post[0];j<post.size()-1;j++)
+                {
+                    if((post[j]+1)!=post[j+1])
+                    {
+                        flag=true;
+                        break;
+                    }
+                }
+                ans++;
+                if(!flag)
+                {
+                    break;
+                }
+                flag=false;
+            }
+            ind++;
+        }
+    }
+    else
+    {
+        ll ind=post[0];
+        bool flag=false;
+        for(i=0;i<post.size();i++)
+        {
+            if(ind!=post[i])
+            {
+                ll back1=post.back();
+                swap(s[ind],s[back1]);
+                posu.push_back(back1);
+                sort(posu.begin(),posu.end());
+                for(j=posu[0];j<posu.size()-1;j++)
+                {
+                    if((posu[j]+1)!=posu[j+1])
+                    {
+                        flag=true;
+                        break;
+                    }
+                }
+                ans++;
+                if(!flag)
+                {
+                    break;
+                }
+                flag=false;
+            }
+            ind++;
+        }
+    }
+    cout<<ans<<endl;
+    return 0;
+}
diff --git a/December-07/C++_AminulIslam254.cpp b/December-07/C++_AminulIslam254.cpp
new file mode 100644
index 0000000..3c10d65
--- /dev/null
+++ b/December-07/C++_AminulIslam254.cpp
@@ -0,0 +1,58 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+typedef long long ll;
+
+int main()
+{
+    ll n;
+    cout<< "Enter the no of buildings"<<endl;
+    cin>>n;
+    ll a[n][6],i,j;
+    cout<< "Enter coordinates"<<endl;
+    for(i=0;i<n;i++)
+    {
+        for(j=0;j<6;j++)
+        {
+            cin>>a[i][j];
+        }
+    }
+    ll num,k;
+    cout<< "Enter the no of jet planes"<<endl;
+    cin>>num;
+    ll store1=0;
+    for(k=0;k<num;k++)
+    {
+        cout<< "Enter axis either x or y"<<endl;
+        char c; cin>>c;
+        cout<< "Enter axis number for x or y"<<endl;
+        ll axisnum;cin>>axisnum;
+        for(i=0;i<n;i++)
+        {
+            bool issmall=false;
+            bool isbig=false;
+            if(c=='x') j=0;
+            if(c=='y') j=1;
+            for(;j<6;j+=2)
+            {
+                if(a[i][j]<axisnum)
+                {
+                    issmall=true;
+                }
+                else if(a[i][j]>axisnum)
+                {
+                    isbig=true;
+                }
+            }
+            if(issmall && isbig)
+            {
+                store1++;
+            }
+        }
+        cout<<store1<<endl;
+        store1=0;
+    }
+
+    return 0;
+}
diff --git a/December-08/C++_AminulIslam254.cpp b/December-08/C++_AminulIslam254.cpp
new file mode 100644
index 0000000..e6695a7
--- /dev/null
+++ b/December-08/C++_AminulIslam254.cpp
@@ -0,0 +1,30 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+typedef long long ll;
+
+int main()
+{
+    ll n;
+    cout<< "Enter the time"<<endl;
+    cin>>n;
+    ll a[n+1]={0},i,current1=3;
+    a[1]=3;
+    for(i=2;i<=n;i++)
+    {
+        if(a[i-1]==1)
+        {
+            current1*=2;
+            a[i]=current1;
+        }
+        else
+        {
+            a[i]=a[i-1]-1;
+        }
+    }
+    cout<<a[n]<<endl;
+
+
+    return 0;
+}
diff --git a/December-09/C++_AminulIslam254.cpp b/December-09/C++_AminulIslam254.cpp
new file mode 100644
index 0000000..5b980c7
--- /dev/null
+++ b/December-09/C++_AminulIslam254.cpp
@@ -0,0 +1,90 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+typedef long long ll;
+
+int main()
+{
+    ll n,p,i;
+    cout<< "Enter the value of n and p"<<endl;
+    cin>>n>>p;
+    vector<ll> a;
+    cout<< "Enter array elements"<<endl;
+    for(i=0;i<n;i++)
+    {
+        ll var1; cin>>var1;
+        a.push_back(var1);
+    }
+    sort(a.begin(),a.end());
+    vector<ll> temp1;
+    for(i=0;i<n-1;i++)
+    {
+        temp1.push_back(a[i+1]-a[i]);
+    }
+    ll min1=INT_MAX,index=-1;
+    for(i=0;i<temp1.size();i++)
+    {
+        if(temp1[i]<min1)
+        {
+            min1=temp1[i];
+            index=i;
+        }
+    }
+    vector<ll> v1;
+    if(index==0)
+    {
+        for(i=0;i<p;i++)
+        {
+            v1.push_back(a[i]);
+        }
+    }
+    else if(index==n-1)
+    {
+        for(i=n-1;i>=p;i--)
+        {
+            v1.push_back(a[i]);
+        }
+    }
+    else
+    {
+        v1.push_back(a[index+1]);
+        ll left=index-1,right=index+1;
+        p=p-1;
+        while(p)
+        {
+            if(left==-1)
+            {
+                v1.push_back(a[right]);
+                right++;
+            }
+            else if(right==n)
+            {
+                v1.push_back(a[left]);
+                left--;
+            }
+            else
+            {
+                if((a[index]-a[left])<(a[right]-a[index]))
+                {
+                    v1.push_back(a[left]);
+                    left--;
+                }
+                else
+                {
+                    v1.push_back(a[right]);
+                    right++;
+                }
+            }
+            p--;
+        }
+    }
+    sort(v1.begin(),v1.end());
+    ll num1=v1[v1.size()-1],ans=0;
+    for(i=v1.size()-2;i>=0;i--)
+    {
+        ans+=(num1-v1[i]);
+    }
+    cout<<ans<<endl;
+    return 0;
+}
diff --git a/December-10/C++_AminulIslam254.cpp b/December-10/C++_AminulIslam254.cpp
new file mode 100644
index 0000000..663e128
--- /dev/null
+++ b/December-10/C++_AminulIslam254.cpp
@@ -0,0 +1,74 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+typedef long long ll;
+
+void fun1(vector<vector<ll>> a,ll n,ll& count1,bool& isend,ll i,ll j,vector<vector<bool>>& maze1)
+{
+    if(i==n)
+    {
+        return;
+    }
+    if(j==n)
+    {
+        return;
+    }
+    if(i==n-1 && j==n-1)
+    {
+        isend=true;
+    }
+    if(a[i][j]==1 && (!maze1[i][j]))
+    {
+        count1++;
+
+    }
+    maze1[i][j]=true;
+    if(a[i][j]==-1)
+    {
+        return;
+    }
+    fun1(a,n,count1,isend,i+1,j,maze1);
+    fun1(a,n,count1,isend,i,j+1,maze1);
+}
+
+int main()
+{
+    cout<< "Enter the no of rows and coloumns"<<endl;
+    ll n; cin>>n;
+    vector<vector<ll>> a;
+    ll i,j;
+    cout<< "Enter the elements"<<endl;
+    for(i=0;i<n;i++)
+    {
+        vector<ll> temp1;
+        for(j=0;j<n;j++)
+        {
+            ll var1; cin>>var1;
+            temp1.push_back(var1);
+        }
+        a.push_back(temp1);
+    }
+    ll count1=0;
+    bool isend=false;
+    vector<vector<bool>> maze1;
+    for(i=0;i<n;i++)
+    {
+        vector<bool>temp2;
+        for(j=0;j<n;j++)
+        {
+            temp2.push_back(false);
+        }
+        maze1.push_back(temp2);
+    }
+    fun1(a,n,count1,isend,0,0,maze1);
+    if(isend)
+    {
+        cout<<count1<<endl;
+    }
+    else
+    {
+        cout<<0<<endl;
+    }
+    return 0;
+}
diff --git a/December-12/C++_AminulIslam254.cpp b/December-12/C++_AminulIslam254.cpp
new file mode 100644
index 0000000..9fe2128
--- /dev/null
+++ b/December-12/C++_AminulIslam254.cpp
@@ -0,0 +1,60 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+typedef long long ll;
+
+int main()
+{
+    cout<< "Enter the no of cars"<<endl;
+    ll n; cin>>n;
+    ll s1[n],i;
+    ll var1;
+    cout<< "Enter the speed of cars"<<endl;
+    for(i=0;i<n;i++)
+    {
+         cin>>s1[i];
+    }
+    stack<ll> ans;
+    ans.push(s1[0]);
+    for(i=1;i<n;i++)
+    {
+        ll var1=s1[i];
+        if((ans.top()>0 && var1>0) || (ans.top()<0 && var1<0))
+        {
+            ans.push(var1);
+        }
+        else
+        {
+            while(1)
+            {
+                ll curr=ans.top();
+                if((abs(var1))>(abs(curr)))
+                {
+                    ans.pop();
+                }
+                else if((abs(var1))==(abs(curr)))
+                {
+                    ans.pop();
+                    break;
+                }
+                else
+                {
+                    break;
+                }
+            }
+        }
+    }
+    stack<ll> temp1;
+    while(!ans.empty())
+    {
+        temp1.push(ans.top());
+        ans.pop();
+    }
+    while(!temp1.empty())
+    {
+        cout<<temp1.top()<< " ";
+        temp1.pop();
+    }
+    return 0;
+}
diff --git a/December-13/C++_AminulIslam254.cpp b/December-13/C++_AminulIslam254.cpp
new file mode 100644
index 0000000..f704269
--- /dev/null
+++ b/December-13/C++_AminulIslam254.cpp
@@ -0,0 +1,54 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+typedef long long ll;
+
+int main()
+{
+    cout<< "Enter the no of diamonds"<<endl;
+    ll x; cin>>x;
+    vector<ll> mp,np;
+    ll i,var1;
+    cout<< "Enter the purity levels of all diamonds"<<endl;
+    for(i=0;i<x;i++)
+    {
+        cin>>var1;
+        mp.push_back(var1);
+    }
+    cout<< "Enter the minimum prices of all diamonds"<<endl;
+    for(i=0;i<x;i++)
+    {
+        cin>>var1;
+        np.push_back(var1);
+    }
+    cout<< "Enter the no of clients"<<endl;
+    ll z; cin>>z;
+    ll k[z],r[z],j;
+    cout<< "Enter the values of k"<<endl;
+    for(i=0;i<z;i++)
+    {
+        cin>>k[i];
+    }
+    cout<< "Enter the values of r"<<endl;
+    for(i=0;i<z;i++)
+    {
+        cin>>r[i];
+    }
+    ll ans=0;
+    for(i=0;i<z;i++)
+    {
+        for(j=0;j<mp.size();j++)
+        {
+            if(mp[j]>k[i] && np[j]<=r[i])
+            {
+                ans++;
+                mp.erase(mp.begin()+j);
+                np.erase(np.begin()+j);
+                break;
+            }
+        }
+    }
+    cout<<ans<<endl;
+    return 0;
+}
diff --git a/December-14/C++_AminulIslam254.cpp b/December-14/C++_AminulIslam254.cpp
new file mode 100644
index 0000000..1f185c4
--- /dev/null
+++ b/December-14/C++_AminulIslam254.cpp
@@ -0,0 +1,69 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+typedef long long ll;
+
+int main()
+{
+    cout<< "Enter the no chapters"<<endl;
+    ll n; cin>>n;
+    ll a[n],i,sum1=0,j;
+    cout<< "Enter the no of concepts for each chapter"<<endl;
+    for(i=0;i<n;i++)
+    {
+        cin>>a[i];
+    }
+    cout<< "Enter the value of x"<<endl;
+    ll x; cin>>x;
+    sort(a,a+n);
+    if(n==x)
+    {
+        cout<<a[n-1]<<endl;
+    }
+    else
+    {
+        for(i=n-2;i>=0;i--)
+        {
+            ll time1=i+1;
+            sum1+=a[i+1];
+            ll rem=sum1%a[i];
+            if(rem==0)
+            {
+                time1+=(sum1/a[i]);
+            }
+            else
+            {
+                 time1+=(sum1/a[i])+1;
+            }
+            bool flag=false;
+            if(time1>=x)
+            {
+                time1=i+1;
+                for(j=a[i]+1;j<=a[i+1];j++)
+                {
+                    rem=sum1%j;
+                    if(rem==0)
+                    {
+                        time1+=(sum1/j);
+                    }
+                    else
+                    {
+                         time1+=(sum1/j)+1;
+                    }
+                    if(time1<x)
+                    {
+                        cout<<j<<endl;
+                        flag=true;
+                        break;
+                    }
+                }
+            }
+            if(flag)
+            {
+                break;
+            }
+        }
+    }
+    return 0;
+}
diff --git a/December-15/C++_AminulIslam254.cpp b/December-15/C++_AminulIslam254.cpp
new file mode 100644
index 0000000..6a9ea59
--- /dev/null
+++ b/December-15/C++_AminulIslam254.cpp
@@ -0,0 +1,37 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+typedef long long ll;
+
+int main()
+{
+    cout<< "Enter the no bracelts"<<endl;
+    ll x; cin>>x;
+    ll a[x],i,sum1=0,time1=0,max1=-1;
+    cout<< "Enter the array"<<endl;
+    for(i=0;i<x;i++)
+    {
+        cin>>a[i];
+        sum1+=a[i];
+        max1=max(max1,a[i]);
+    }
+    cout<< "Enter the value of n"<<endl;
+    ll n; cin>>n;
+    for(i=max1;;i++)
+    {
+        time1=sum1/i;
+        if(sum1%i!=0)
+        {
+            time1++;
+        }
+        if(time1<=n)
+        {
+            cout<<i<<endl;
+            break;
+        }
+
+    }
+
+    return 0;
+}
diff --git a/December-16/C++_AminulIslam254.cpp b/December-16/C++_AminulIslam254.cpp
new file mode 100644
index 0000000..e506a36
--- /dev/null
+++ b/December-16/C++_AminulIslam254.cpp
@@ -0,0 +1,53 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+typedef long long ll;
+
+int main()
+{
+    cout<< "Enter the no of test cases"<<endl;
+    ll t; cin>>t;
+    while(t--)
+    {
+        ll x;
+        cout<< "Enter the no of rangers"<<endl;
+
+        cin>>x;
+        ll a[x],i;
+        cout<< "Enter the position of the rangers"<<endl;
+        ll odd1=0,even1=0;
+        for(i=0;i<x;i++)
+        {
+            cin>>a[i];
+            if(a[i]%2==0)
+            {
+                even1++;
+            }
+            else
+            {
+                odd1++;
+            }
+        }
+        cout<< "Enter the position of leo"<<endl;
+        ll pos; cin>>pos;
+        if(odd1==0 || even1==0)
+        {
+            cout<<x<< " "<<1<<endl;
+        }
+        else
+        {
+            if(odd1>even1)
+            {
+                cout<<odd1<< " "<<-1<<endl;
+            }
+            else
+            {
+                cout<<even1<< " "<<-1<<endl;
+            }
+        }
+
+    }
+
+    return 0;
+}
diff --git a/December-17/C++_AminulIslam254.cpp b/December-17/C++_AminulIslam254.cpp
new file mode 100644
index 0000000..d2b912f
--- /dev/null
+++ b/December-17/C++_AminulIslam254.cpp
@@ -0,0 +1,39 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+typedef long long ll;
+
+int main()
+{
+    cout<< "Enter the size for each task"<<endl;
+    ll n; cin>>n;
+    ll task_size[n],process_time[n],noof_task[n],i;
+    cout<< "Enter the elements for task size"<<endl;
+    for(i=0;i<n;i++)
+    {
+        cin>>task_size[i];
+    }
+    cout<< "Enter the elements for processing time"<<endl;
+    for(i=0;i<n;i++)
+    {
+        cin>>process_time[i];
+    }
+    cout<< "Enter the elements for no of tasks"<<endl;
+    for(i=0;i<n;i++)
+    {
+        cin>>noof_task[i];
+    }
+    ll ans=0,time1=0;
+    for(i=0;i<n;i++)
+    {
+        time1=noof_task[i]/task_size[i];
+        if(noof_task[i]%task_size[i]!=0)
+        {
+            time1++;
+        }
+        ans=max(ans,(time1*process_time[i]));
+    }
+    cout<<ans<<endl;
+    return 0;
+}
diff --git a/December-18/C++_AminulIslam254.cpp b/December-18/C++_AminulIslam254.cpp
new file mode 100644
index 0000000..6bee17a
--- /dev/null
+++ b/December-18/C++_AminulIslam254.cpp
@@ -0,0 +1,29 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+typedef long long ll;
+
+int main()
+{
+    cout<< "Enter the size of matrix"<<endl;
+    ll n; cin>>n;
+    ll a[n][n],i,j;
+    ll pos[2][2],k=0;
+    cout<< "Enter the no of elements"<<endl;
+    for(i=0;i<n;i++)
+    {
+        for(j=0;j<n;j++)
+        {
+            cin>>a[i][j];
+            if(a[i][j]==1)
+            {
+                pos[k][0]=i;
+                pos[k][1]=j;
+                k++;
+            }
+        }
+    }
+    cout<<abs(pos[1][0]-pos[0][0])+abs(pos[1][1]-pos[0][1])-1<<endl;
+    return 0;
+}
diff --git a/December-19/C++_AminulIslam254.cpp b/December-19/C++_AminulIslam254.cpp
new file mode 100644
index 0000000..f330ebc
--- /dev/null
+++ b/December-19/C++_AminulIslam254.cpp
@@ -0,0 +1,46 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+typedef long long ll;
+
+int main()
+{
+    cout<< "Enter the size of matrix"<<endl;
+    ll n,i,j; cin>>n;
+    cout<< "Enter the courses"<<endl;
+    vector<set<ll>> v1(n);
+    for(i=0;i<n;i++)
+    {
+        ll a1,a2;
+        cin>>a1>>a2;
+        for(auto x:v1[a1])
+        {
+            v1[i].insert(a2);
+        }
+        v1[a1].insert(a2);
+
+    }
+    cout<< "Enter the size for the answer matrix"<<endl;
+    ll size1; cin>>size1;
+    vector<bool> ans;
+    cout<< "Enter the elements for the answer matrix"<<endl;
+    for(i=0;i<size1;i++)
+    {
+        ll a1,a2;
+        cin>>a1>>a2;
+        if(v1[a1].count(a2))
+        {
+            ans.push_back(true);
+        }
+        else
+        {
+            ans.push_back(false);
+        }
+    }
+    for(i=0;i<ans.size();i++)
+    {
+        cout<<ans[i]<< " ";
+    }
+    return 0;
+}
diff --git a/December-20/C++_AminulIslam254.cpp b/December-20/C++_AminulIslam254.cpp
new file mode 100644
index 0000000..7092cfb
--- /dev/null
+++ b/December-20/C++_AminulIslam254.cpp
@@ -0,0 +1,78 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+typedef long long ll;
+
+int main()
+{
+    cout<< "Enter the value of n"<<endl;
+    ll n,i; cin>>n;
+    cout<< "Enter the size of the load"<<endl;
+    ll size1;cin>>size1;
+    ll load[size1];
+    cout<< "Enter the load of all the processes"<<endl;
+    for(i=0;i<size1;i++)
+    {
+        cin>>load[i];
+    }
+    int server[n]={0},j,count1[n]={0};
+    for(i=0;i<size1;i++)
+    {
+        for(j=0;j<n;j++)
+        {
+            server[j]-=1;
+        }
+        ll temp1=load[i]%n;
+        if(server[temp1]!=0)
+        {
+            bool flag=false;
+            for(j=(temp1+1)%n;j<n;j++)
+            {
+                j=j%n;
+                if(server[j]==0)
+                {
+                    flag=true;
+                    server[j]=load[i];
+                    count1[j]++;
+                    break;
+                }
+            }
+            if(!flag)
+            {
+                int min1=INT_MAX,index1=0;
+                for(j=0;j<n;j++)
+                {
+                    if(server[j]<min1)
+                    {
+                        min1=server[j];
+                        index1=j;
+                    }
+                }
+                for(j=0;j<n;j++)
+                {
+                    server[j]-=min1;
+                }
+                server[index1]=load[i];
+                count1[index1]++;
+            }
+
+        }
+        else
+        {
+            server[temp1]=load[i];
+            count1[temp1]++;
+        }
+    }
+    int ans=-1,index1=-1;
+    for(i=0;i<n;i++)
+    {
+        if(count1[i]>ans)
+        {
+            ans=count1[i];
+            index1=i;
+        }
+    }
+    cout<<index1<<endl;
+    return 0;
+}
diff --git a/December-21/C++_AminulIslam254.cpp b/December-21/C++_AminulIslam254.cpp
new file mode 100644
index 0000000..501794f
--- /dev/null
+++ b/December-21/C++_AminulIslam254.cpp
@@ -0,0 +1,94 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+typedef long long ll;
+
+int main()
+{
+
+    cout<< "Enter the value of x"<<endl;
+    ll x; cin>>x;
+    ll a[x][x],i,j,noof1s=0,noof0s=0;
+    cout<< "Enter the elements of array"<<endl;
+    for(i=0;i<x;i++)
+    {
+        for(j=0;j<x;j++)
+        {
+            cin>>a[i][j];
+            if(a[i][j])
+            {
+                noof1s++;
+            }
+            else
+            {
+                noof0s++;
+            }
+        }
+    }
+    ll var1=(x*x)/2;
+    ll var2=(x*x)-var1;
+    if(var1==noof0s && var2==noof1s)
+    {
+        ll col0=0,flag=0;
+        for(i=0;i<x;i++)
+        {
+            for(j=0;j<x;j++)
+            {
+               if(!a[j][i])
+               {
+                   col0++;
+               }
+            }
+            if(col0!=(x/2))
+            {
+                flag=1;
+                break;
+            }
+            col0=0;
+        }
+        if(flag)
+        {
+            cout<<-1<<endl;
+        }
+        else
+        {
+            ll anomaly=0,count1=1;
+            j=1;
+            for(i=0;i<x;i++)
+            {
+                for(;j<x;j+=2)
+                {
+                   if(!a[j][i])
+                   {
+                       anomaly++;
+                   }
+                }
+                if(count1)
+                {
+                    count1=0;
+                    j=0;
+                }
+                else
+                {
+                    count1=1;
+                    j=1;
+                }
+            }
+            if(anomaly==0)
+            {
+                cout<<0<<endl;
+            }
+            else
+            {
+                cout<<anomaly/2<<endl;
+            }
+        }
+    }
+    else
+    {
+        cout<<-1<<endl;
+    }
+
+    return 0;
+}
diff --git a/December-23/C++_AminulIslam254.cpp b/December-23/C++_AminulIslam254.cpp
new file mode 100644
index 0000000..d554f3a
--- /dev/null
+++ b/December-23/C++_AminulIslam254.cpp
@@ -0,0 +1,47 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+typedef long long ll;
+
+void makegraph(vector<set<ll>> &v1,ll a,ll b)
+{
+    v1[a].insert(b);
+    v1[b].insert(a);
+}
+
+void fun1(vector<set<ll>>& v1,ll head,ll &count1)
+{
+    for(auto x:v1[head])
+    {
+        if(x==1)
+        {
+            count1++;
+            v1[head].erase(v1[head].begin());
+            return;
+        }
+        else
+        {
+            fun1(v1,x,count1);
+        }
+    }
+    return;
+}
+
+int main()
+{
+
+    cout<< "Enter the value of x and y"<<endl;
+    ll x,y,i; cin>>x>>y;
+    vector<set<ll>> v1(y+1);
+     cout<< "Enter the values of a and b"<<endl;
+    for(i=0;i<y;i++)
+    {
+        ll a,b; cin>>a>>b;
+        makegraph(v1,a,b);
+    }
+    ll count1=0;
+    fun1(v1,1,count1);
+    cout<<count1<<endl;
+    return 0;
+}