Contains duplicate

Array Hash Table Sorting

64.1% acceptance

Jan 12, 2026

13810

1361

Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct.

Solution

Rust

Time O(n)

Space O(n)

LeetCode

solution.rs

impl Solution {
  pub fn contains_duplicate(nums: Vec<i32>) -> bool {
    let mut seen = std::collections::HashSet::new();
    for num in nums {
      if !seen.insert(num) {
        return true;
      }
    }
    false
  }
}