Row with maximum ones

Array Matrix

74.3% acceptance

Feb 25, 2026

594

Given a m x n binary matrix mat, find the 0-indexed position of the row that contains the maximum count of ones, and the number of ones in that row. In case there are multiple rows that have the maximum count of ones, the row with the smallest row number should be selected. Return an array containing the index of the row, and the number of ones in it.

Solution

Rust

Time O(n)

Space O(n)

LeetCode

solution.rs

impl Solution {
  pub fn row_and_maximum_ones(mat: Vec<Vec<i32>>) -> Vec<i32> {
    let mut best_row = 0;
    let mut best_count = 0;
    for (i, row) in mat.iter().enumerate() {
      let count = row.iter().filter(|&&x| x == 1).count();
      if count > best_count {
        best_count = count;
        best_row = i;
      }
    }
    vec![best_row as i32, best_count as i32]
  }
}