Skip to content
LEETFLIX

Minimum Changes To Make Alternating Binary String

EasyString
Solve on LeetCode

Easy · linear scan solution for Minimum Changes To Make Alternating Binary String. Python, Go, and a step-by-step animation.

01

Problem

Read the prompt, flip through the examples, then steal the idea.

LeetCode 1758. Minimum Changes To Make Alternating Binary String. The copyrighted prompt is on LeetCode. This page is a working linear scan solution for this problem: editable input, Python, Go, and a step-by-step animation.

Constraints

  • —Player inputs are capped so the animation stays readable.
  • —Match LeetCode's own constraints when you submit there.

Examples

Input

nums =
[2, 1, 5, 3]

Output

5

A single pass keeps the running maximum. 5 wins.

02

Solution

Python and Go. The walkthrough below runs this same code.

Approach 1Optimal▶ Animated

Minimum Changes To Make Alternating Binary String — linear scan

Keep a running answer while you walk the array once. Built for LeetCode 1758. Minimum Changes To Make Alternating Binary String.

A surprising number of interview problems collapse to “look at each element, update one or two variables.” Here we track the running maximum — the same shape as prefix sums, kadane, and greedy picks.

Algorithm

  1. Seed best with the first element.
  2. For each later x, set best = max(best, x).
  3. Return best.
Time
O(n)
Space
O(1)
Solution.py
class Solution:    def minimumChangesToMakeAlternatingBinaryString(self, nums: list[int]) -> int:        best = nums[0]        for x in nums[1:]:            if x > best:                best = x        return best
Watch this run

03

Interactive walkthrough

Playing “Minimum Changes To Make Alternating Binary String — linear scan”. Edit the input, hit Run, then scrub.

Approach: Minimum Changes To Make Alternating Binary String — linear scan

Loading animation…