Sort colors

Array Two Pointers Sorting

69.2% acceptance

Jan 12, 2026

21433

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Given an array nums with n objects colored red, white, or blue, sort them in-place so that objects of the same color are adjacent, with the colors in the order red, white, and blue. We will use the integers 0, 1, and 2 to represent the color red, white, and blue, respectively. You must solve this problem without using the library's sort function.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn sort_colors(nums: &mut Vec<i32>) {
    let mut low = 0;
    let mut mid = 0;
    let mut high = nums.len() - 1;
    
    while mid <= high {
      match nums[mid] {
        0 => {
          nums.swap(low, mid);
          low += 1;
          mid += 1;
        },
        1 => {
          mid += 1;
        },
        _ => {
          nums.swap(mid, high);
          if high == 0 {
            break;
          }
          high -= 1;
        }
      }
    }
  }
}