Missing ranges

Array

35.5% acceptance

Apr 1, 2026

1182

3021

You are given an inclusive range [lower, upper] and a sorted unique integer array nums, where all elements are within the inclusive range. A number x is considered missing if x is in the range [lower, upper] and x is not in nums. Return the shortest sorted list of ranges that exactly covers all the missing numbers. That is, no element of nums is included in any of the ranges, and each missing number is covered by one of the ranges.

Solution

Rust

Time O(n)

Space O(n)

LeetCode

solution.rs

impl Solution {
  pub fn find_missing_ranges(nums: Vec<i32>, lower: i32, upper: i32) -> Vec<Vec<i32>> {
    let mut result = Vec::new();
    let mut prev = lower as i64 - 1;
    let nums_ext: Vec<i64> = nums.iter().map(|&x| x as i64).chain(std::iter::once(upper as i64 + 1)).collect();
    for &num in &nums_ext {
      if num - prev >= 2 {
        result.push(vec![(prev + 1) as i32, (num - 1) as i32]);
      }
      prev = num;
    }
    result
  }
}