leetcode.jp 博客
本网站所有文字及图片内容均来自网络,每周定时更新,仅供个人学习与研究,请勿用于商业用途。谢谢合作。

1526. Minimum Number of Increments on Subarrays to Form a Target Array

Given an array of positive integers target and an array initial of same size with all zeros.

Return the minimum number of operations to form a target array from initial if you are allowed to do the following operation:

  • Choose any subarray from initial and increment each value by one.
The answer is guaranteed to fit within the range of a 32-bit signed integer.

 

Example 1:

Input: target = [1,2,3,2,1]
Output: 3
Explanation: We need at least 3 operations to form the target array from the initial array.
[0,0,0,0,0] increment 1 from index 0 to 4 (inclusive).
[1,1,1,1,1] increment 1 from index 1 to 3 (inclusive).
[1,2,2,2,1] increment 1 at index 2.
[1,2,3,2,1] target array is formed.

Example 2:

Input: target = [3,1,1,2]
Output: 4
Explanation: (initial)[0,0,0,0] -> [1,1,1,1] -> [1,1,1,2] -> [2,1,1,2] -> [3,1,1,2] (target).

Example 3:

Input: target = [3,1,5,4,2]
Output: 7
Explanation: (initial)[0,0,0,0,0] -> [1,1,1,1,1] -> [2,1,1,1,1] -> [3,1,1,1,1] 
                                  -> [3,1,2,2,2] -> [3,1,3,3,2] -> [3,1,4,4,2] -> [3,1,5,4,2] (target).

Example 4:

Input: target = [1,1,1,1]
Output: 1

 

Constraints:

  • 1 <= target.length <= 10^5
  • 1 <= target[i] <= 10^5

Difficulty:

Hard

Lock:

Normal

Company:

Google

Solution(Chinese):

LEETCODE 1526. Minimum Number of Increments on Subarrays to Form a Target Array 解题思路分析