Minimum cost to make all characters equal

String Dynamic Programming Greedy

54.2% acceptance

Feb 25, 2026

582

You are given a 0-indexed binary string s of length n on which you can apply two types of operations: Choose an index i and invert all characters from index 0 to index i (both inclusive), with a cost of i + 1 Choose an index i and invert all characters from index i to index n - 1 (both inclusive), with a cost of n - i Return the minimum cost to make all characters of the string equal.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn minimum_cost(s: String) -> i64 {
    let s = s.as_bytes();
    let n = s.len() as i64;
    let mut cost = 0i64;
    for i in 1..s.len() {
      if s[i] != s[i - 1] {
        cost += (i as i64).min(n - i as i64);
      }
    }
    cost
  }
}