题目描述
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.
image
Above is a histogram where width of each bar is 1, given height = [2,1,5,6,2,3]
image
The largest rectangle is shown in the shaded area, which has area = 10
unit.
Example:
Input: [2,1,5,6,2,3] Output: 10
思路
用栈来模拟,遍历heights数组,如果大于栈顶元素,就push进去;否则,持续弹栈来计算从栈顶点到降序点的矩阵大小。然后将这一部分全部替换为降序点的值,即做到了整体依然是有序非降的。
整个过程中,即把所有的局部最大矩阵计算过了,又在宽度范围内保留了全部的场景。
代码实现
class Solution: def largestRectangleArea(self, height): height.append(0) stack = [-1] ans = 0 for i in range(len(height)): while height[i] < height[stack[-1]]: h = height[stack.pop()] w = i - stack[-1] - 1 ans = max(ans, h * w) stack.append(i) height.pop() return ans