Image smoother

Array Matrix

69.1% acceptance

Feb 20, 2026

1237

2995

Given an m x n integer matrix img representing a grayscale image, return the smoothed version where every pixel is replaced by the average of itself and its surrounding pixels (8-directional), rounded down.

Solution

Rust

Time O(n * m)

Space O(n * m)

LeetCode

solution.rs

impl Solution {
  pub fn image_smoother(img: Vec<Vec<i32>>) -> Vec<Vec<i32>> {
    let m = img.len();
    let n = img[0].len();
    let mut result = vec![vec![0i32; n]; m];
    for i in 0..m {
      for j in 0..n {
        let mut sum = 0;
        let mut count = 0;
        for di in -1i32..=1 {
          for dj in -1i32..=1 {
            let ni = i as i32 + di;
            let nj = j as i32 + dj;
            if ni >= 0 && ni < m as i32 && nj >= 0 && nj < n as i32 {
              sum += img[ni as usize][nj as usize];
              count += 1;
            }
          }
        }
        result[i][j] = sum / count;
      }
    }
    result
  }
}