Pairs of songs with total durations divisible by 60

Array Hash Table Counting

53.4% acceptance

Feb 25, 2026

4326

182

You are given a list of songs where the ith song has a duration of time[i] seconds. Return the number of pairs of songs for which their total duration in seconds is divisible by 60. Formally, we want the number of indices i, j such that i < j with (time[i] + time[j]) % 60 == 0.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn num_pairs_divisible_by60(time: Vec<i32>) -> i32 {
    let mut cnt = [0i32; 60];
    let mut ans = 0;
    for t in time {
      let r = (t % 60) as usize;
      ans += cnt[(60 - r) % 60];
      cnt[r] += 1;
    }
    ans
  }
}