Largest Rectangle in Histogram
问题描述：
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.
参考答案：
class Solution {
public:
int largestRectangleArea(vector<int>& heights) {
stack<int> s;
int i = 0;
int maxarea = 0;
while (i < heights.size()) {
if (s.empty() || heights[i] >= heights[s.top()])
s.push(i++);
else {
int h = heights[s.top()];
s.pop();
int w = s.empty() ? i : i-s.top()-1;
maxarea = max(maxarea, h*w);
}
}
while (!s.empty()) {
int h = heights[s.top()];
s.pop();
int w = s.empty() ? i : i-s.top()-1;
maxarea = max(maxarea, h*w);
}
return maxarea;
}
};