CCF_ 201312-3_最大的矩形

遍历数组中每一元素，左右延伸得出宽度。

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

int main()
{
    int n,a[],sum = ;
    cin >> n;
    for(int i = ;i <= n;i++)    cin >> a[i];
    for(int i = ;i <= n;i++)
    {
        int j,left = -,right = -;
        for(j = i-;j > ;j--)
        {
            if(a[j] < a[i])
            {
                left = j;
                break;
            }
        }
        if(left == -)    left = ;
        for(j = i+;j <= n;j++)
        {
            if(a[j] < a[i])
            {
                right = j;
                break;
            }
        }
        if(right == -)    right =    n+;
        sum = max(sum,(right-left-)*a[i]);
    }
    cout << sum << endl;
    return ;
}