leetcode - 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.

For example,

Given height =

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

,

return

10

.

class Solution {
public:
int largestRectangleArea(std::vector<int> &height) {
height.push_back(0);
std::stack<int> s;
int i = 0;
int maxArea = 0;
while (i < height.size())
{
if(s.empty() || height[s.top()] <= height[i])
{
s.push(i++);
}
else
{
int t = s.top();
s.pop();
maxArea = std::max(maxArea,height[t]*(s.empty() ? i : i - s.top() - 1));
}
}
return maxArea;
}
};