1240. 完全二叉树的权值

思路：
双指针算法

代码：

# include<iostream>
# include<cstdio>
# include<cstring>
# include<algorithm>
using namespace std;

typedef long long LL;

const int N = 100010;
int a[N];
int n;

int main()
{
    
    
    scanf("%d",&n);
    for(int i = 1;i <= n;i++)
    {
    
    
        scanf("%d",&a[i]);
    }
    int depth = 0;
    LL maxn = -1e18;
    for(int i = 1,d = 1;i <= n;i *= 2,d++)
    {
    
    
        LL s = 0;
        for(int j = i;j < i + (1 << d - 1) && j <= n;j++)
        {
    
    
            s += a[j];
        }
        if(s > maxn)
        {
    
    
            maxn = s;
            depth = d;
        }
    }
    printf("%d",depth);
    return 0;
}