Gray code

Math Backtracking Bit Manipulation

64.1% acceptance

Jan 12, 2026

2521

2832

An n-bit gray code sequence is a sequence of 2n integers where: Every integer is in the inclusive range [0, 2n - 1], The first integer is 0, An integer appears no more than once in the sequence, The binary representation of every pair of adjacent integers differs by exactly one bit, and The binary representation of the first and last integers differs by exactly one bit. Given an integer n, return any valid n-bit gray code sequence.

Solution

Rust

Time O(n²)

Space O(n)

LeetCode

solution.rs

impl Solution {
  pub fn gray_code(n: i32) -> Vec<i32> {
    let mut result = vec![0];
    
    for i in 0..n {
      let size = result.len();
      let mask = 1 << i;
      for j in (0..size).rev() {
        result.push(result[j] | mask);
      }
    }
    
    result
  }
}