#Leetcode# 84. Largest Rectangle in Histogram

https://leetcode.com/problems/largest-rectangle-in-histogram/

 

Given n non-negative integers representing the histogram's bar height where the width of each bar is 1, find the area of largest rectangle in the histogram.

 

Above is a histogram where width of each bar is 1, given height = [2,1,5,6,2,3].

 

The largest rectangle is shown in the shaded area, which has area = 10 unit.

 

Example:

Input: [2,1,5,6,2,3]
Output: 10

代码：

class Solution {
public:
    int largestRectangleArea(vector<int>& heights) {
        int ans = 0;
        int n = heights.size();
        for(int i = 0; i < n; i ++) {
            if(i + 1 < n && heights[i] <= heights[i + 1]) continue;
            int minn = heights[i];
            for(int j = i; j >= 0; j --) {
                minn = min(minn, heights[j]);
                int maxx = minn * (i - j + 1);
                ans = max(ans, maxx);
            }
        }
        return ans;
    }
};