Minimum moves to get a peaceful board

Array Greedy Sorting Counting Sort

75.9% acceptance

Mar 31, 2026

Given a 2D array rooks of length n, where rooks[i] = [xi, yi] indicates the position of a rook on an n x n chess board. Your task is to move the rooks 1 cell at a time vertically or horizontally (to an adjacent cell) such that the board becomes peaceful. A board is peaceful if there is exactly one rook in each row and each column. Return the minimum number of moves required to get a peaceful board. Note that at no point can there be two rooks in the same cell.

Solution

Rust

Time O(n log n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn min_moves(rooks: Vec<Vec<i32>>) -> i32 {
    let n = rooks.len();
    let mut rows: Vec<i32> = rooks.iter().map(|r| r[0]).collect();
    let mut cols: Vec<i32> = rooks.iter().map(|r| r[1]).collect();
    rows.sort_unstable();
    cols.sort_unstable();
    let mut total = 0;
    for i in 0..n {
      total += (rows[i] - i as i32).abs() + (cols[i] - i as i32).abs();
    }
    total
  }
}