数组里面的数但凡多一点就超时(恼

#include <iostream>
#include<string>

using namespace std;
int a[101][101];
int main() {
    int n,sum=0;
    string zhiyin;
    cin>>n>>zhiyin;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            cin>>a[i][j];  
        }
    }
    if(zhiyin=="lr"){
       for(int i=0;i<n;i++){
           sum+=a[i][i];
       }
    }
    if(zhiyin=="rl"){
        for(int i=n;i>=0;i++){
            sum+=a[i][i];
        }
    }
    
    cout<<sum<<endl;
    return 0;
}