Plus one

Array Math

49.6% acceptance

Jan 12, 2026

11731

5597

You are given a large integer represented as an integer array digits, where each digits[i] is the ith digit of the integer. The digits are ordered from most significant to least significant in left-to-right order. The large integer does not contain any leading 0's. Increment the large integer by one and return the resulting array of digits.

Solution

Rust

Time O(n)

Space O(n)

LeetCode

solution.rs

impl Solution {
  pub fn plus_one(mut digits: Vec<i32>) -> Vec<i32> {
    for i in (0..digits.len()).rev() {
      if digits[i] < 9 {
        digits[i] += 1;
        return digits;
      }
      digits[i] = 0;
    }
    
    // If we reach here, all digits were 9
    let mut result = vec![1];
    result.extend(digits);
    result
  }
}