4 solutions

  • 1
    @ 2026-2-23 11:23:18
    #include<bits/stdc++.h>
    using namespace std;
    int c(int n){
    	if(n==1){
    		return 1;
    	}
    	return n+c(n-1);
    }
    int main(){
    	int cnt = 0,n;
    	cin>>n;
    	for(int i=1;i<=n;i++){
    		cnt += c(i);
    	}
    	cout<<cnt;
    }
    
    
    • 0
      @ 2026-1-25 11:59:52
      #include<bits/stdc++.h>
      using namespace std;
      int main()
      {
          int n;
          cin>>n;
          long long s=0;
          for(int i=1;i<=n;i++)
          {
              s+=((1+i)*i/2);
          }
          cout<<s;
      }
      
      • -1
        @ 2026-1-27 19:32:27
        #include <iostream>
        using namespace std;
        int main(){
            int n;
            cin>>n;
            cout<<n*(n+1)*(n+2)/6<<endl;
            return 0;
        }
        
        • -2
          @ 2025-11-27 11:54:18

          C++ :

          #include<bits/stdc++.h>
          using namespace std;
          int c(int n){
          	if(n==1){
          		return 1;
          	}
          	return n+c(n-1);
          }
          int main(){
          	int cnt = 0,n;
          	cin>>n;
          	for(int i=1;i<=n;i++){
          		cnt += c(i);
          	}
          	cout<<cnt;
          }
          
          • 1

          Information

          ID
          20
          Time
          1000ms
          Memory
          128MiB
          Difficulty
          7
          Tags
          # Submissions
          16
          Accepted
          11
          Uploaded By