Check balanced string

String

82.5% acceptance

Feb 23, 2026

139

You are given a string num consisting of only digits. A string of digits is called balanced if the sum of the digits at even indices is equal to the sum of digits at odd indices. Return true if num is balanced, otherwise return false.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn is_balanced(num: String) -> bool {
    let (even_sum, odd_sum) = num.bytes().enumerate().fold((0i32, 0i32), |(e, o), (i, b)| {
      let d = (b - b'0') as i32;
      if i % 2 == 0 { (e + d, o) } else { (e, o + d) }
    });
    even_sum == odd_sum
  }
}