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
.
题意:求直方图中最大面积的矩形。
思路:单调栈的应用。维持一个单调递增的栈,网上写的可以转来:题解
- public class Solution {
- public int largestRectangleArea(int[] height) {
- Stack<Integer> stack = new Stack<Integer>();
- int i = 0;
- int ans = 0;
- int h[] = new int[height.length+1];
- h = Arrays.copyOf(height, height.length+1);
- while (i < h.length) {
- if (stack.isEmpty() || h[stack.peek()] <= h[i])
- stack.push(i++);
- else {
- int t = stack.pop();
- ans = Math.max(ans, h[t] * (stack.isEmpty() ? i : i - stack.peek() - 1));
- }
- }
- return ans;
- }
- }