leetcode

Leetcode problem solutions
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2923-find-champion-i.rs (2126B)

      1/// 2923. Find Champion I (Easy)
      2///
      3/// There are n teams numbered from 0 to n - 1 in a tournament.
      4///
      5/// Given a *0-indexed* 2D boolean matrix grid of size n * n. For all i, j that
      6/// 0 <= i, j <= n - 1 and i != j team i is *stronger* than team j if grid[i][j]
      7/// == 1, otherwise, team j is *stronger* than team i.
      8///
      9/// Team a will be the *champion* of the tournament if there is no team b that
     10/// is stronger than team a.
     11///
     12/// Return the team that will be the champion of the tournament.
     13///
     14/// *Example 1:*
     15///
     16///   *Input:* grid = [[0,1],[0,0]]
     17///   *Output:* 0
     18///   *Explanation:* There are two teams in this tournament.
     19///   grid[0][1] == 1 means that team 0 is stronger than team 1. So team 0 will be
     20///   the champion.
     21///
     22/// *Example 2:*
     23///
     24///   *Input:* grid = [[0,0,1],[1,0,1],[0,0,0]]
     25///   *Output:* 1
     26///   *Explanation:* There are three teams in this tournament.
     27///   grid[1][0] == 1 means that team 1 is stronger than team 0.
     28///   grid[1][2] == 1 means that team 1 is stronger than team 2.
     29///   So team 1 will be the champion.
     30///
     31/// *Constraints:*
     32///
     33///   * n == grid.length
     34///   * n == grid[i].length
     35///   * 2 <= n <= 100
     36///   * grid[i][j] is either 0 or 1.
     37///   * For all i grid[i][i] is 0.
     38///   * For all i, j that i != j, grid[i][j] != grid[j][i].
     39///   * The input is generated such that if team a is stronger than team b and
     40///   team b is stronger than team c, then team a is stronger than team c.
     41///
     42use leetcode::*;
     43
     44struct Solution {}
     45
     46impl Solution {
     47    pub fn find_champion(grid: Vec<Vec<i32>>) -> i32 {
     48        for (y, row) in grid.iter().enumerate() {
     49            if row.iter().sum::<i32>() == row.len() as i32 - 1 && row[y] == 0 {
     50                return y as i32;
     51            }
     52        }
     53        unreachable!()
     54    }
     55}
     56
     57pub fn main() {
     58    println!("{}", Solution::find_champion(arg_into(1)));
     59}
     60
     61#[cfg(test)]
     62mod tests {
     63    use crate::Solution;
     64    use leetcode::vvi;
     65
     66    #[test]
     67    fn test() {
     68        assert_eq!(Solution::find_champion(vvi("[[0,1],[0,0]]")), 0);
     69        assert_eq!(Solution::find_champion(vvi("[[0,0,1],[1,0,1],[0,0,0]]")), 1);
     70    }
     71}