LeetCode OJ 之 Largest Rectangle in Histogram （直方图中的最大矩形）

题目：

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.

给n个非负数代表直方图每个长条的高度，每个长条的宽度是1，找出直方图中最大的矩形。



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.

For example,

Given height = 

[2,1,5,6,2,3]

,

return 

10

.

思路：

参考：http://blog.csdn.net/doc_sgl/article/details/11805519 。

代码：

class Solution {
public:
int largestRectangleArea(vector<int> &height)
{
stack<int> stk;
height.push_back(0);
int maxArea = 0;
for(int i = 0 ; i < height.size() ; )
{
if(stk.empty() || height[i] > height[stk.top()])
{
stk.push(i);
i++;
}
else
{
int tmp = stk.top();
stk.pop();
maxArea = max(maxArea , height[tmp] * (stk.empty() ? i : (i - stk.top() - 1)));//Largest Rectangle in Histogram ???
}
}
return maxArea;
}
};