73. Set Matrix Zeroes
Given an m x n matrix. If an element is 0, set its entire row and column to 0. Do it in-place.
Follow up:
- A straight forward solution using O(mn) space is probably a bad idea.
- A simple improvement uses O(m + n) space, but still not the best solution.
- Could you devise a constant space solution?
Example 1:
Input: matrix = [[1,1,1],[1,0,1],[1,1,1]] Output: [[1,0,1],[0,0,0],[1,0,1]]
Example 2:
Input: matrix = [[0,1,2,0],[3,4,5,2],[1,3,1,5]] Output: [[0,0,0,0],[0,4,5,0],[0,3,1,0]]
Constraints:
m == matrix.lengthn == matrix[0].length1 <= m, n <= 200-231 <= matrix[i][j] <= 231 - 1
Rust Solution
struct Solution;
use std::collections::HashSet;
impl Solution {
fn set_zeroes(matrix: &mut Vec<Vec<i32>>) {
let mut row: HashSet<usize> = HashSet::new();
let mut col: HashSet<usize> = HashSet::new();
let n = matrix.len();
let m = matrix[0].len();
for i in 0..n {
for j in 0..m {
if matrix[i][j] == 0 {
row.insert(i);
col.insert(j);
}
}
}
for i in 0..n {
for j in 0..m {
if row.contains(&i) || col.contains(&j) {
matrix[i][j] = 0;
}
}
}
}
}
#[test]
fn test() {
let mut matrix: Vec<Vec<i32>> = vec_vec_i32![[1, 1, 1], [1, 0, 1], [1, 1, 1]];
let res: Vec<Vec<i32>> = vec_vec_i32![[1, 0, 1], [0, 0, 0], [1, 0, 1]];
Solution::set_zeroes(&mut matrix);
assert_eq!(matrix, res);
let mut matrix: Vec<Vec<i32>> = vec_vec_i32![[0, 1, 2, 0], [3, 4, 5, 2], [1, 3, 1, 5]];
let res: Vec<Vec<i32>> = vec_vec_i32![[0, 0, 0, 0], [0, 4, 5, 0], [0, 3, 1, 0]];
Solution::set_zeroes(&mut matrix);
assert_eq!(matrix, res);
}
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