Description
Given an array A of integers, a ramp is a tuple (i, j) for which i < j and A[i] <= A[j]. The width of such a ramp is j - i.
Find the maximum width of a ramp in A. If one doesn’t exist, return 0.
给定一个整数数组 A，坡是元组 (i, j)，其中 i < j 且 A[i] <= A[j]。这样的坡的宽度为 j - i。
找出 A 中的坡的最大宽度，如果不存在，返回 0 。
题目链接：https://leetcode.com/problems/maximum-width-ramp/
Difficulty: medium
Example 1:
Input: [6,0,8,2,1,5]
Output: 4
Explanation:
The maximum width ramp is achieved at (i, j) = (1, 5): A[1] = 0 and A[5] = 5.
Example 2:
Input: [9,8,1,0,1,9,4,0,4,1]
Output: 7
Explanation:
The maximum width ramp is achieved at (i, j) = (2, 9): A[2] = 1 and A[9] = 1.
Note:
- 2 <= A.length <= 50000
- 0 <= A[i] <= 50000
分析
- updating（Solution）
参考代码
class Solution(object):
def maxWidthRamp(self, A):
ans = 0
m = float('inf')
for i in sorted(range(len(A)), key = A.__getitem__):
ans = max(ans, i - m)
m = min(m, i)
return ans