diff --git a/December 01/c++_dArK-sEiD05_01.cpp b/December 01/c++_dArK-sEiD05_01.cpp
new file mode 100644
index 0000000..1f41503
--- /dev/null
+++ b/December 01/c++_dArK-sEiD05_01.cpp	
@@ -0,0 +1,19 @@
+#include <iostream>
+#include <vector>
+using namespace std;
+
+int findMissingNumber(int N, vector<int> &array) {
+    int totalSum = N * (N + 1) / 2;
+    int arraySum = 0;
+    for (int num : array) {
+        arraySum += num;
+    }
+    return totalSum - arraySum;
+}
+
+int main() {
+    int N = 5;
+    vector<int> array = {1, 2, 4, 5};
+    cout << findMissingNumber(N, array) << endl;
+    return 0;
+}
diff --git a/December 02/c++_dArK-sEiD05_02.cpp.cpp b/December 02/c++_dArK-sEiD05_02.cpp.cpp
new file mode 100644
index 0000000..9851ec2
--- /dev/null
+++ b/December 02/c++_dArK-sEiD05_02.cpp.cpp	
@@ -0,0 +1,31 @@
+
+#include <iostream>
+#include <vector>
+using namespace std;
+int main() {
+    // Write C++ code here
+    vector <int> arr= {10, 5, 6, 3, 2, 20, 100}
+;
+    
+  
+    for (int i = 1; i < arr.size(); i += 2) {
+     
+        if(arr[i - 1] < arr[i]) {
+            swap(arr[i - 1], arr[i]);
+        }
+      
+        if(i+1<arr.size()&&arr[i]>arr[i + 1]) {
+            swap(arr[i], arr[i + 1]);
+        }
+    }
+  
+    
+    
+    for(int i=0;i<arr.size();i++){
+        cout<<arr[i]<<"\t";
+    }
+    
+   
+
+    return 0;
+}
\ No newline at end of file
diff --git a/December 03/c++_dArK-sEiD05_03.cpp b/December 03/c++_dArK-sEiD05_03.cpp
new file mode 100644
index 0000000..d1dc7f9
--- /dev/null
+++ b/December 03/c++_dArK-sEiD05_03.cpp	
@@ -0,0 +1,18 @@
+#include <iostream>
+using namespace std;
+int main() {
+    
+   int r,b;
+   cout<<"Enter red boxes:";
+   cin>>r;
+   cout<<"Enter blue boxes:";
+   cin>>b;cout<<r<<b<<abs(r-b);
+   if(abs(r-b)==1){
+       cout<<"Not possible";
+   }
+   else{
+       cout<<"Possible";
+   }
+
+    return 0;
+}
diff --git a/December 04/c++_dArK-sEiD05_04.cpp b/December 04/c++_dArK-sEiD05_04.cpp
new file mode 100644
index 0000000..1b39578
--- /dev/null
+++ b/December 04/c++_dArK-sEiD05_04.cpp	
@@ -0,0 +1,15 @@
+#include <iostream>
+using namespace std;
+
+int main() {
+    int n;
+    cout<<"Enter months:";
+   cin>>n;
+   int i=1;int a=1;int b=1;
+   if(n==1 || n==2){cout<<1;}
+   while(i<=n-2){
+       int c=a+b;a=b;b=c;i++;
+   }
+   cout<<b;
+    return 0;
+}
\ No newline at end of file
diff --git a/December 05/c++_dArK-sEiD05_05.cpp b/December 05/c++_dArK-sEiD05_05.cpp
new file mode 100644
index 0000000..de0ac66
--- /dev/null
+++ b/December 05/c++_dArK-sEiD05_05.cpp	
@@ -0,0 +1,20 @@
+
+#include <iostream>
+using namespace std;
+
+int main() {
+    
+    int n,k;
+    cout<<"Enter persons:";
+   cin>>n;
+   cout<<"Enter k:";
+   cin>>k;
+   int i=1;int ans=0;
+   while(i<=5){
+       ans=(ans+k)%i;
+       i++;
+   }
+   cout<<ans+1;
+   
+    return 0;
+}
\ No newline at end of file
diff --git a/December 06/c++_dArK-sEiD05_06.cpp b/December 06/c++_dArK-sEiD05_06.cpp
new file mode 100644
index 0000000..258029b
--- /dev/null
+++ b/December 06/c++_dArK-sEiD05_06.cpp	
@@ -0,0 +1,44 @@
+// Online C++ compiler to run C++ program online
+#include <iostream>
+using namespace std;
+#include <vector>
+#include <unordered_map>
+int main() {
+    int n;
+    cout << "Enter the size of the vector: ";
+    cin >> n;
+
+    vector<int> vec(n); 
+    cout<<"Enter target:";
+    int tar;
+    cin>>tar;
+
+    cout << "Enter " << n << " elements: ";
+    for (int i = 0; i < n; i++) {
+        cin >> vec[i];
+    }
+
+    vector<pair<int, int>> pairs;
+    unordered_map<int,int> hm;
+    for(int i=0;i<n;i++){
+        hm[vec[i]]++;
+    }
+    for(int i=0;i<n;i++){
+        if(hm.find((tar-vec[i]))!=0 && hm[abs(vec[i]-tar)]>0){
+            if(vec[i]*2==tar){
+                if(hm[vec[i]]>1){
+                    pairs.push_back({vec[i],(tar-vec[i])});
+                    hm.erase(vec[i]);
+                    
+                }
+            }else{
+            pairs.push_back({vec[i],(tar-vec[i])});
+            hm[vec[i]]--;hm[vec[i]-tar]--;
+        }}
+    }
+    for (const auto& p : pairs) {
+        cout << "(" << p.first << ", " << p.second << ")" << endl;
+    }
+   
+    return 0;
+}
\ No newline at end of file
diff --git a/December 07/c++_dArK-sEiD05_07.cpp b/December 07/c++_dArK-sEiD05_07.cpp
new file mode 100644
index 0000000..b668a06
--- /dev/null
+++ b/December 07/c++_dArK-sEiD05_07.cpp	
@@ -0,0 +1,37 @@
+
+#include <iostream>
+using namespace std;
+#include<vector>
+int main() {
+    int n;
+    cout << "Enter the size of the vector: ";
+    cin >> n;
+    vector<vector<int>> ans;
+    ans.push_back({1});
+    for (int i=1;i<=n;i++){
+        vector<int> temp;
+        int x=0;
+        while(x<=i){
+            int sum=0;
+            if (x < ans[i - 1].size()) {
+                sum += ans[i - 1][x];
+            }
+            if (x - 1 >= 0) {
+                sum += ans[i - 1][x - 1];
+            }
+            
+            temp.push_back(sum);x++;
+        }
+        ans.push_back(temp);
+        }
+        
+    
+    for(int i=0;i<n;i++){
+        for(int j=0;j<ans[i].size();j++){
+            cout<<ans[i][j]<<"\t";
+        }
+        cout<<"\n";
+    }
+   
+    return 0;
+}
\ No newline at end of file
diff --git a/December 08/c++_dArK-sEiD05_08.cpp b/December 08/c++_dArK-sEiD05_08.cpp
new file mode 100644
index 0000000..594b67b
--- /dev/null
+++ b/December 08/c++_dArK-sEiD05_08.cpp	
@@ -0,0 +1,22 @@
+// Online C++ compiler to run C++ program online
+#include <iostream>
+using namespace std;
+#include<vector>
+int main() {
+    int n;
+    cout << "Enter the size: ";
+    cin >> n;int i=1;int sum=0;
+    while(i<=n){
+        int k=i;
+        while(k>0){
+            int x=k%10;
+            sum+=x*x;
+            k=k/10;
+        }
+        i++;
+    }
+    cout<<sum;
+    
+   
+    return 0;
+}
\ No newline at end of file
diff --git a/December 09/c++_dArK-sEiD05_09.cpp b/December 09/c++_dArK-sEiD05_09.cpp
new file mode 100644
index 0000000..78e45d6
--- /dev/null
+++ b/December 09/c++_dArK-sEiD05_09.cpp	
@@ -0,0 +1,32 @@
+// Online C++ compiler to run C++ program online
+#include <iostream>
+#include <sstream>
+#include <vector>
+#include <string>
+using namespace std;
+
+
+int main() {
+    
+  int n;
+  cout<<"Enter number of elements:";
+  cin>>n;
+  vector<int> vec(n);
+  
+  for(int i=0;i<n;i++){
+      cin>>vec[i];
+  }
+  int cnt=0;
+  for(int i=0;i<vec.size();i++){
+      if(vec[i]==1){
+          cnt++;
+      }
+  }
+  cout<<"Occurance"<<cnt;
+    
+    
+    
+   
+
+    return 0;
+}
\ No newline at end of file
diff --git a/December 10/c++_dArK-sEiD05_10.cpp b/December 10/c++_dArK-sEiD05_10.cpp
new file mode 100644
index 0000000..167a1ee
--- /dev/null
+++ b/December 10/c++_dArK-sEiD05_10.cpp	
@@ -0,0 +1,84 @@
+#include <iostream>
+#include <vector>
+#include <queue>
+#include <unordered_map>
+#include <unordered_set>
+
+using namespace std;
+
+vector<vector<string>> findTaskOrder(const vector<pair<string, vector<string>>> &tasks) {
+    unordered_map<string, vector<string>> graph;
+    unordered_map<string, int> in_degree;
+    unordered_set<string> all_tasks;
+
+    for (const auto &task : tasks) {
+        string current = task.first;
+        all_tasks.insert(current);
+
+        for (const string &dependency : task.second) {
+            graph[dependency].push_back(current);
+            in_degree[current]++;
+            all_tasks.insert(dependency);
+        }
+    }
+
+    queue<string> q;
+    for (const string &task : all_tasks) {
+        if (in_degree[task] == 0) {
+            q.push(task);
+        }
+    }
+
+    vector<vector<string>> result;
+
+    while (!q.empty()) {
+        vector<string> concurrent_tasks;
+        int size = q.size();
+
+        for (int i = 0; i < size; ++i) {
+            string task = q.front();
+            q.pop();
+            concurrent_tasks.push_back(task);
+
+            for (const string &neighbor : graph[task]) {
+                in_degree[neighbor]--;
+                if (in_degree[neighbor] == 0) {
+                    q.push(neighbor);
+                }
+            }
+        }
+
+        result.push_back(concurrent_tasks);
+    }
+
+    for (const auto &entry : in_degree) {
+        if (entry.second > 0) {
+            throw runtime_error("Error: Cyclic dependency detected");
+        }
+    }
+
+    return result;
+}
+
+int main() {
+    vector<pair<string, vector<string>>> tasks = {
+        {"TaskA", {}},
+        {"TaskB", {"TaskA"}},
+        {"TaskC", {"TaskB"}},
+        {"TaskD", {"TaskB", "TaskC"}}
+    };
+
+    try {
+        vector<vector<string>> order = findTaskOrder(tasks);
+        for (const auto &level : order) {
+            for (const string &task : level) {
+                cout << task << " ";
+            }
+            cout << endl;
+        }
+    } catch (const runtime_error &e) {
+        cout << e.what() << endl;
+    }
+
+    return 0;
+}
diff --git a/December 11/c++_dArK-sEiD05_11.cpp b/December 11/c++_dArK-sEiD05_11.cpp
new file mode 100644
index 0000000..1540fab
--- /dev/null
+++ b/December 11/c++_dArK-sEiD05_11.cpp	
@@ -0,0 +1,29 @@
+#include <iostream>
+#include <string>
+using namespace std;
+
+bool judgeCircle(string moves) {
+    int x = 0, y = 0; 
+    for (char move : moves) {
+        if (move == 'R') x++;    
+        else if (move == 'L') x--; 
+        else if (move == 'U') y++; 
+        else if (move == 'D') y--; 
+    }
+
+    return (x == 0 && y == 0);
+}
+
+int main() {
+    string moves;
+    cout << "Enter the moves: ";
+    cin >> moves;
+
+    if (judgeCircle(moves)) {
+        cout << "The robot returns to the origin." << endl;
+    } else {
+        cout << "The robot does not return to the origin." << endl;
+    }
+
+    return 0;
+}
diff --git a/December 12/c++_dArK-sEiD05_12.cpp b/December 12/c++_dArK-sEiD05_12.cpp
new file mode 100644
index 0000000..0348893
--- /dev/null
+++ b/December 12/c++_dArK-sEiD05_12.cpp	
@@ -0,0 +1,74 @@
+// Online C++ compiler to run C++ program online
+#include <iostream>
+#include <sstream>
+#include <vector>
+#include <string>
+using namespace std;
+vector<string> splitStringBySpace(const string &str) {
+    vector<string> tokens;
+    stringstream ss(str);
+    string word;
+
+   
+    while (ss >> word) {
+        tokens.push_back(word);
+    }
+    return tokens;
+}
+
+int main() {
+    
+    
+    vector<string> ans;
+    
+    vector<string> arr={"Eve 4","Diana 3 VIP","Adam 5","Frank 6 VIP"};
+    
+   int total;
+   cout<<"Enter total tickets";
+   cin>>total;bool visited[arr.size()]={false};
+    for(int i=0;i<arr.size();i++){
+        if(total>0){
+       vector<string> result = splitStringBySpace(arr[i]);
+       if(result[result.size()-1]=="VIP"){
+           string userw=result[1];int a=stoi(userw);
+           if(a>total){userw=to_string(total);}
+           string str=result[0]+" purchased "+userw+" tickets";
+           ans.push_back(str);
+           total-=stoi(userw);
+          visited[i]=true;
+       }
+    }else{break;}}
+    for(int i=0;i<arr.size();i++){
+         vector<string> result = splitStringBySpace(arr[i]);
+        if(total>0){
+      
+       if(result[result.size()-1]!="VIP"){
+           string userw=result[1];int a=stoi(userw);
+           if(a>total){userw=to_string(total);}
+           string str=result[0]+" purchased "+userw+" tickets";
+           ans.push_back(str);
+           total-=stoi(userw);visited[i]=true;
+           
+       }
+    }else{
+      break;
+        
+    }}
+    for(int i=0;i<arr.size();i++){
+        if(visited[i]==false){ 
+            vector<string> result = splitStringBySpace(arr[i]);
+            
+            string str=result[0]+" no tickets ";
+           ans.push_back(str);}
+    }
+    
+    for(int i=0;i<ans.size();i++){
+        cout<<ans[i]<<"\n";
+    }
+   
+    
+    
+   
+
+    return 0;
+}
\ No newline at end of file
diff --git a/December 13/c++_dArK-sEiD05_13.cpp b/December 13/c++_dArK-sEiD05_13.cpp
new file mode 100644
index 0000000..9118cad
--- /dev/null
+++ b/December 13/c++_dArK-sEiD05_13.cpp	
@@ -0,0 +1,57 @@
+#include <iostream>
+#include <sstream>
+#include <vector>
+#include <string>
+
+using namespace std;
+
+void swap(vector<int>& arr, int i, int j)
+{
+    int temp = arr[i];
+    arr[i] = arr[j];
+    arr[j] = temp;
+}
+
+
+
+int minSwaps(vector<int> arr, int N)
+{
+    int ans = 0;
+    vector<int> temp = arr;
+
+    
+    map<int, int> h;
+
+    sort(temp.begin(), temp.end());
+    for (int i = 0; i < N; i++) {
+        h[arr[i]] = i;
+    }
+    for (int i = 0; i < N; i++) {
+    
+      
+        if (arr[i] != temp[i]) {
+            ans++;
+            int init = arr[i];
+
+            swap(arr, i, h[temp[i]]);
+
+            h[init] = h[temp[i]];
+            h[temp[i]] = i;
+        }
+    }
+    return ans;
+}
+
+
+int main()
+{   int n;
+    cout<<"Enter length:";
+    cin>>n;
+    vector<int> a(n);
+    cout<<"Enter elements:";
+    for(int i=0;i<n;i++){
+        cin>>a[i];
+    }
+   
+    cout << minSwaps(a, n);
+}
diff --git a/December 14/c++_dArK-sEiD05_14.cpp b/December 14/c++_dArK-sEiD05_14.cpp
new file mode 100644
index 0000000..a7d4167
--- /dev/null
+++ b/December 14/c++_dArK-sEiD05_14.cpp	
@@ -0,0 +1,39 @@
+#include <iostream>
+#include <unordered_map>
+#include <vector>
+using namespace std;
+
+string canSplitSquad(int N, int K, int D, const vector<int> &A) {
+    unordered_map<int, int> subject_counts;
+    for (int subject : A) {
+        subject_counts[subject]++;
+    }
+
+    int unique_subjects = subject_counts.size();
+    if (unique_subjects < K) {
+        return "NO";
+    }
+
+    int max_team_size = (N + D) / 2;
+    int min_team_size = (N - D) / 2;
+
+    int count_within_limit = 0;
+    for (const auto &entry : subject_counts) {
+        if (entry.second <= min_team_size) {
+            count_within_limit++;
+        }
+    }
+
+    if (count_within_limit < K) {
+        return "NO";
+    }
+
+    return "YES";
+}
+
+int main() {
+    int N = 10, K = 3, D = 2;
+    vector<int> A = {1, 2, 2, 3, 3, 3, 4, 5, 5, 5};
+    cout << canSplitSquad(N, K, D, A) << endl;
+    return 0;
+}
diff --git a/December 15/c++_dArK-sEiD05_15.cpp b/December 15/c++_dArK-sEiD05_15.cpp
new file mode 100644
index 0000000..3e48b62
--- /dev/null
+++ b/December 15/c++_dArK-sEiD05_15.cpp	
@@ -0,0 +1,40 @@
+// Online C++ compiler to run C++ program online
+#include <iostream>
+#include <sstream>
+#include <vector>
+#include <string>
+using namespace std;
+
+
+int main() {
+    
+    int trips=0;int n;
+  cout<<"Enter number of houses:";
+  cin>>n;
+  vector<int> houses(n);
+  
+  for(int i=0;i<n;i++){
+      cin>>houses[i];
+  }
+  int w;
+  cout<<"Enter weight:";
+  cin>>w;
+  int i=0;
+  while(i<n){
+      int currseq=0;
+      while(currseq+houses[i]<=w && i<n){
+          
+          currseq+=houses[i];i++;cout<<currseq;
+          
+      }
+     
+      trips++;
+  }
+  cout<<"trips:"<<trips;
+    
+    
+    
+   
+
+    return 0;
+}
\ No newline at end of file
diff --git a/December 16/c++_dArK-sEiD05_16.cpp b/December 16/c++_dArK-sEiD05_16.cpp
new file mode 100644
index 0000000..70c39c1
--- /dev/null
+++ b/December 16/c++_dArK-sEiD05_16.cpp	
@@ -0,0 +1,38 @@
+#include <iostream>
+#include <vector>
+#include <algorithm>
+
+using namespace std;
+
+int min_platforms(vector<int>& arrivals, vector<int>& departures) {
+    sort(arrivals.begin(), arrivals.end());
+    sort(departures.begin(), departures.end());
+
+    int platforms_needed = 0;
+    int current_platforms = 0;
+
+    int i = 0, j = 0;
+
+    while (i < arrivals.size()) {
+        if (arrivals[i] <= departures[j]) {
+            current_platforms++;
+            i++;
+        } else {
+            current_platforms--;
+            j++;
+        }
+
+        platforms_needed = max(platforms_needed, current_platforms);
+    }
+
+    return platforms_needed;
+}
+
+int main() {
+    vector<int> arrivals = {100, 180, 270, 320, 450};
+    vector<int> departures = {200, 250, 350, 400, 500};
+
+    cout << "Minimum platforms required: " << min_platforms(arrivals, departures) << endl;
+
+    return 0;
+}
diff --git a/December 17/c++_dArK-sEiD05_17.cpp b/December 17/c++_dArK-sEiD05_17.cpp
new file mode 100644
index 0000000..9982401
--- /dev/null
+++ b/December 17/c++_dArK-sEiD05_17.cpp	
@@ -0,0 +1,97 @@
+#include <iostream>
+#include <unordered_map>
+#include <deque>
+#include <vector>
+#include <string>
+#include <chrono>
+#include <queue>
+#include <algorithm>
+
+using namespace std;
+
+class AlertManager {
+private:
+    struct Alert {
+        chrono::system_clock::time_point timestamp;
+        int threat_level;
+
+        bool operator>(const Alert& other) const {
+            return timestamp > other.timestamp;
+        }
+    };
+
+    unordered_map<string, Alert> alerts;
+    priority_queue<pair<chrono::system_clock::time_point, string>, vector<pair<chrono::system_clock::time_point, string>>, greater<>> alert_queue;
+    unordered_map<string, chrono::system_clock::time_point> last_seen;
+    chrono::minutes alert_expiry_time = chrono::minutes(5);
+    chrono::seconds duplicate_time_limit = chrono::seconds(30);
+
+    chrono::system_clock::time_point str_to_time(const string& timestamp) {
+        int hours, minutes, seconds;
+        sscanf(timestamp.c_str(), "%d:%d:%d", &hours, &minutes, &seconds);
+        auto time = chrono::hours(hours) + chrono::minutes(minutes) + chrono::seconds(seconds);
+        return chrono::system_clock::now() - time;
+    }
+
+public:
+    void process_alert(const string& alert_id, const string& timestamp, int threat_level) {
+        chrono::system_clock::time_point current_time = str_to_time(timestamp);
+
+        if (last_seen.find(alert_id) != last_seen.end() &&
+            chrono::duration_cast<chrono::seconds>(current_time - last_seen[alert_id]) < duplicate_time_limit) {
+            return; // Skip duplicate alert
+        }
+
+        if (alerts.find(alert_id) == alerts.end() || current_time > alerts[alert_id].timestamp) {
+            alerts[alert_id] = {current_time, threat_level};
+            alert_queue.push({current_time, alert_id});
+        }
+
+        last_seen[alert_id] = current_time;
+    }
+
+    vector<pair<string, pair<string, int>>> get_alerts() {
+        chrono::system_clock::time_point current_time = chrono::system_clock::now();
+        vector<pair<string, pair<string, int>>> valid_alerts;
+
+        while (!alert_queue.empty() &&
+               chrono::duration_cast<chrono::minutes>(current_time - alert_queue.top().first) > alert_expiry_time) {
+            string expired_alert_id = alert_queue.top().second;
+            alert_queue.pop();
+            alerts.erase(expired_alert_id); // Remove expired alerts
+        }
+
+        for (const auto& alert : alerts) {
+            const auto& alert_data = alert.second;
+            if (chrono::duration_cast<chrono::minutes>(current_time - alert_data.timestamp) <= alert_expiry_time) {
+                valid_alerts.push_back({alert.first, {"Timestamp: " + to_string(chrono::duration_cast<chrono::seconds>(alert_data.timestamp.time_since_epoch()).count()), alert_data.threat_level}});
+            }
+        }
+
+        return valid_alerts;
+    }
+};
+
+int main() {
+    AlertManager alert_manager;
+
+    vector<pair<string, pair<string, int>>> alerts = {
+        {"A123", {"00:00:10", 3}},
+        {"A123", {"00:00:15", 3}},
+        {"B456", {"00:00:20", 2}},
+        {"A123", {"00:00:30", 5}},
+        {"B456", {"00:05:05", 2}}
+    };
+
+    for (const auto& alert : alerts) {
+        alert_manager.process_alert(alert.first, alert.second.first, alert.second.second);
+    }
+
+    vector<pair<string, pair<string, int>>> stored_alerts = alert_manager.get_alerts();
+    for (const auto& alert : stored_alerts) {
+        cout << "Alert ID: " << alert.first << ", Timestamp: " << alert.second.first
+             << ", Threat Level: " << alert.second.second << endl;
+    }
+
+    return 0;
+}
diff --git a/December 18/c++_dArK-sEiD05_18.cpp b/December 18/c++_dArK-sEiD05_18.cpp
new file mode 100644
index 0000000..0c69d83
--- /dev/null
+++ b/December 18/c++_dArK-sEiD05_18.cpp	
@@ -0,0 +1,36 @@
+// Online C++ compiler to run C++ program online
+#include <iostream>
+#include <string>
+using namespace std;
+int main() {
+    // Write C++ code here
+    string str="RDEREDR";int start;int end;int max=-1;
+    for(int i=0;i<(str.size());i++){
+        int k=i;int j=i;int mid=0;int curr=1;
+        while(k>=0 && j<(str.size()) ){
+            
+            if(str[k]==str[j] ){
+                curr+=2;
+                if(curr>max){
+                    start=k;end=j;mid=i;max=curr;
+                }
+                
+            }
+            k--;j++;
+        }
+    }
+    
+    int sum=0;
+    for(int i=start;i<=end;i++){
+        if(str[i]=='D')
+            sum+=500;
+        
+        else if(str[i]=='R')
+        sum+=250;
+        else if(str[i]=='E')
+        sum+=100;
+    }
+    
+    cout<<sum*(end-start+1);
+    return 0;
+}
\ No newline at end of file
diff --git a/December 19/c++_dArK-sEiD05_19.cpp b/December 19/c++_dArK-sEiD05_19.cpp
new file mode 100644
index 0000000..70384d8
--- /dev/null
+++ b/December 19/c++_dArK-sEiD05_19.cpp	
@@ -0,0 +1,40 @@
+#include <iostream>
+#include <vector>
+#include <string>
+
+using namespace std;
+
+vector<pair<string, string>> tower_of_hanoi(int n, string source, string destination, string auxiliary) {
+    vector<pair<string, string>> moves;
+    
+    if (n == 0) {
+        return moves;
+    }
+
+    vector<pair<string, string>> first_half = tower_of_hanoi(n - 1, source, auxiliary, destination);
+    moves.insert(moves.end(), first_half.begin(), first_half.end());
+    
+    moves.push_back({source, destination});
+    
+    vector<pair<string, string>> second_half = tower_of_hanoi(n - 1, auxiliary, destination, source);
+    moves.insert(moves.end(), second_half.begin(), second_half.end());
+    
+    return moves;
+}
+
+int main() {
+    int num_disks = 4;
+    string start = "A";
+    string destination = "C";
+    string auxiliary = "B";
+
+    vector<pair<string, string>> moves = tower_of_hanoi(num_disks, start, destination, auxiliary);
+
+    cout << "Minimum number of moves: " << moves.size() << endl;
+    cout << "Sequence of moves:" << endl;
+    for (int i = 0; i < moves.size(); i++) {
+        cout << i + 1 << ". Move disk from " << moves[i].first << " to " << moves[i].second << endl;
+    }
+
+    return 0;
+}
diff --git a/December 20/c++_dArK-sEiD05_20.cpp b/December 20/c++_dArK-sEiD05_20.cpp
new file mode 100644
index 0000000..8f16496
--- /dev/null
+++ b/December 20/c++_dArK-sEiD05_20.cpp	
@@ -0,0 +1,37 @@
+#include <iostream>
+#include <vector>
+using namespace std;
+
+int countPermutations(vector<int>& steps, int distance) {
+    // Create a DP array initialized to 0
+    
+    vector<int> dp(distance + 1, 0);
+    
+    // Base case: 1 way to reach distance 0
+    dp[0] = 1;
+    
+    // Fill the DP array
+    for (int j = 1; j <= distance; j++) {
+        for (int s : steps) {
+            if (j >= s) {
+                dp[j] += dp[j - s];
+            }
+            
+        }
+        cout<<"\n";
+        cout<<j<<"\n";
+        for(int s:dp){
+            cout<<s<<" ";
+        }
+    }
+    
+    return dp[distance];
+}
+
+int main() {
+    vector<int> steps = {1, 2, 3}; // Example step sizes
+    int distance = 4;             // Example target distance
+    
+    cout << "Number of distinct ways: " << countPermutations(steps, distance) << endl;
+    return 0;
+}
diff --git a/December 21/c++_dArK-sEiD05_21.cpp b/December 21/c++_dArK-sEiD05_21.cpp
new file mode 100644
index 0000000..2c819e1
--- /dev/null
+++ b/December 21/c++_dArK-sEiD05_21.cpp	
@@ -0,0 +1,79 @@
+// Online C++ compiler to run C++ program online
+#include <iostream>
+using namespace std;
+
+
+struct Node {
+    int data;
+    Node* next;
+    Node(int val) : data(val), next(nullptr) {}
+};
+
+
+Node* createLinkedList(int arr[], int size) {
+    if (size == 0) return nullptr;
+    Node* head = new Node(arr[0]);
+    Node* current = head;
+    for (int i = 1; i < size; ++i) {
+        current->next = new Node(arr[i]);
+        current = current->next;
+    }
+    return head;
+}
+void attachLists(Node* list1, Node* list2, int position) {
+    if (position == 0) return; 
+    Node* current = list1;
+    for (int i = 1; i < position && current != nullptr; ++i) {
+        current = current->next;
+    }
+    if (current != nullptr) {
+        Node* temp = list2;
+        while (temp->next != nullptr) {
+            temp = temp->next;
+        }
+        temp->next = current;
+    }
+}
+
+int main() {
+ 
+    int n;
+    cout << "Enter the number of nodes in the first linked list: ";
+    cin >> n;
+    int arr1[n];
+    cout << "Enter the node values: ";
+    for (int i = 0; i < n; ++i) {
+        cin >> arr1[i];
+    }
+    int m;
+    cout << "Enter the number of nodes in the second linked list: ";
+    cin >> m;
+    int arr2[m];
+    cout << "Enter the node values: ";
+    for (int i = 0; i < m; ++i) {
+        cin >> arr2[i];
+    }
+    int pos;
+    cout << "Enter the position of intersection (0 if no intersection): ";
+    cin >> pos;
+
+ 
+    Node* list1 = createLinkedList(arr1, n);
+    Node* list2 = createLinkedList(arr2, m);
+
+    attachLists(list1, list2, pos);
+
+    if (pos == 0) {
+        cout << "No intersection found." << endl;
+    } else {
+        Node* current = list1;
+        for (int i = 1; i < pos && current != nullptr; ++i) {
+            current = current->next;
+        }
+        if (current) {
+            cout << "The intersection point is: " << current->data << endl;
+        }
+    }
+
+    return 0;
+}