一开始写的代码只过了小部分样例, 如果数很大的话就WA了。
下面是一开始的代码:

C++ 代码

#include<iostream>
#include<vector>

using namespace std;

vector<int> a;

int main(){
    int n, x;
    scanf("%d", &n);

    for(int i = 0; i < n; i++){
        scanf("%d", &x);
        a.push_back(x);
    }

    int maxSum = -1e9, sum, ansDep = 1;
    for(int i = 0, j = 1, dep = 1; i < a.size(); i++, dep++){
        sum = 0;
        for(int k = i, m = 0; k < a.size() && m < j; m++,k++) sum += a[k];
        if(maxSum < sum){
            maxSum = sum;
            ansDep =  dep;
        }
        j *= 2;
        i = j - 2;
    }

    cout << ansDep << endl;

    return 0;
}

下面是改后的代码将maxSum 和 sum 都定义为long long类型的了。

C++ 代码

#include<iostream>
#include<vector>

using namespace std;

vector<int> a;

int main(){
    int n, x;
    scanf("%d", &n);

    for(int i = 0; i < n; i++){
        scanf("%d", &x);
        a.push_back(x);
    }

    long long maxSum = a[0], sum;
    int ansDep = 1;
    for(int i = 0, j = 1, dep = 1; i < a.size(); dep++){
        sum = 0;
        for(int k = i, m = 0; k < a.size() && m < j; m++,k++) sum += a[k];
        if(maxSum < sum){
            maxSum = sum;
            ansDep =  dep;
        }

        j *= 2;
        i = j - 1;
    }

    cout << ansDep << endl;

    return 0;
}