Minimum Number of Increments on Subarrays to Form a Target Array — LeetCode 1526 Python Solution

HardStackGreedyArrayDynamic ProgrammingMonotonic Stack

Problem: #1526
Pattern: Stack
Reading time: 2 min
Source: leetcode.com

The problem

You are given an integer array target. You have an integer array initial of the same size as target with all elements initially zeros.

Example

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.

Python solution

Python

class Solution:
    def minNumberOperations(self, target: List[int]) -> int:
        return target[0] + sum(max(0, b - a) for a, b in pairwise(target))

Complexity

Measure	Complexity
Time	O(n), where n is the length of the array target
Space	O(1) auxiliary

Pattern: Stack

When the most recent unresolved thing is the one that matters, use a stack. LeetCode 1526. Minimum Number of Increments on Subarrays to Form a Target Array is filed here because LeetCode tags it Stack, which is the vocabulary this hub collects.

The stack guide has the Python template for the pattern and the 194 LeetCode problems that use it.

Frequently asked questions

How hard is LeetCode 1526. Minimum Number of Increments on Subarrays to Form a Target Array?: LeetCode 1526. Minimum Number of Increments on Subarrays to Form a Target Array is rated Hard on LeetCode.
What is the time complexity of LeetCode 1526. Minimum Number of Increments on Subarrays to Form a Target Array?: The Python solution on this page runs in O(n), where n is the length of the array target.
What is the space complexity of LeetCode 1526. Minimum Number of Increments on Subarrays to Form a Target Array?: The Python solution on this page uses O(1) auxiliary space.
What topics does LeetCode 1526. Minimum Number of Increments on Subarrays to Form a Target Array cover?: LeetCode 1526. Minimum Number of Increments on Subarrays to Form a Target Array is tagged Stack, Greedy, Array, Dynamic Programming and Monotonic Stack on LeetCode.