本题采用模仿栈的方式，先进后出，

最后记录一下我一开始不理解的地方，为什么是r[i] - l[i] - 1;因为一开始默认最右面是n + 1, 最左边是0，（例子：如果第一个点i它右边没有比它高的，那么它的r[i] = 2,左边l[i] = 0, 但它宽度只有1，所以这样算）

C++ 代码

#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;

typedef long long LL;

const int N = 100010;

int n;
int h[N], l[N], r[N];
int top;
int stk[N];

int main()
{
    while (scanf("%d", &n), n != 0)
    {
        for (int i = 1; i <= n; i ++ )
            scanf("%d", &h[i]);

        top = 0;
        stk[++ top] = 0;
        h[0] = h[n + 1] = -1;

        for (int i = 1; i <= n; i ++ )
        {
            while (h[stk[top]] >= h[i]) top --;
            l[i] = stk[top];
            stk[++ top] = i;
        }

        top = 0;
        stk[++ top] = n + 1;
        for (int i = n; i >= 1; i -- )
        {
            while (h[stk[top]] >= h[i]) top --;
            r[i] = stk[top];
            stk[++ top] = i;
        }

        LL res = 0;
        for (int i = 1; i <= n; i ++ )
            res = max(res, (LL)h[i] * (r[i] - l[i] - 1));

        cout << res << endl;
    }
}