Check if a string contains all binary codes of size k

Hash Table String Bit Manipulation Rolling Hash Hash Function

61.5% acceptance

Feb 25, 2026

2709

116

Given a binary string s and an integer k, return true if every binary code of length k is a substring of s, or false otherwise.

Solution

Rust

Time O(n)

Space O(n)

LeetCode

solution.rs

use std::collections::HashSet;

impl Solution {
  pub fn has_all_codes(s: String, k: i32) -> bool {
    let k = k as usize;
    let need = 1usize << k;
    if s.len() < k { return false; }
    let mut seen = HashSet::new();
    for i in 0..=(s.len() - k) {
      seen.insert(&s[i..i + k]);
      if seen.len() == need { return true; }
    }
    seen.len() == need
  }
}