Missing number

Array Hash Table Math Binary Search Bit Manipulation Sorting

71.7% acceptance

Jan 12, 2026

14190

3467

Given an array nums containing n distinct numbers in the range [0, n], return the only number in the range that is missing from the array.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn missing_number(nums: Vec<i32>) -> i32 {
    let n = nums.len() as i32;
    let expected_sum = n * (n + 1) / 2;
    let actual_sum: i32 = nums.iter().sum();
    expected_sum - actual_sum
  }
}