Find players with zero or one losses

Array Hash Table Sorting Counting

72.5% acceptance

Feb 25, 2026

2266

159

You are given an integer array matches where matches[i] = [winneri, loseri] indicates that the player winneri defeated player loseri in a match. Return a list answer of size 2 where: answer[0] is a list of all players that have not lost any matches. answer[1] is a list of all players that have lost exactly one match. The values in the two lists should be returned in increasing order. Note: You should only consider the players that have played at least one match. The testcases will be generated such that no two matches will have the same outcome.

Solution

Rust

Time O(n log n)

Space O(n)

LeetCode

solution.rs

use std::collections::HashMap;


impl Solution {
  pub fn find_winners(matches: Vec<Vec<i32>>) -> Vec<Vec<i32>> {
    let mut losses: HashMap<i32, i32> = HashMap::new();
    for m in &matches {
      let (w, l) = (m[0], m[1]);
      losses.entry(w).or_insert(0);
      *losses.entry(l).or_insert(0) += 1;
    }
    let mut zero_losses: Vec<i32> = losses.iter().filter(|&(_, &v)| v == 0).map(|(&k, _)| k).collect();
    let mut one_loss: Vec<i32> = losses.iter().filter(|&(_, &v)| v == 1).map(|(&k, _)| k).collect();
    zero_losses.sort();
    one_loss.sort();
    vec![zero_losses, one_loss]
  }
}