Official
A - Triangular Number Editorial by en_translator
One can use a for statement to find the sum from \(1\) to \(N\).
Alternatively, one can use the formula \(1+2+\cdots+N=\frac{N(N+1)}{2}\) to find the answer.
Sample code in C++:
#include <bits/stdc++.h>
using namespace std;
int main() {
int n, ans=0;
cin >> n;
for(int i=1;i<=n;i++){
ans+=i;
}
cout << ans << endl;
return 0;
}
Sample code in Python:
n=int(input())
ans=0
for i in range(1,n+1):
ans+=i
print(ans)
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