Today I have done leetcode's January LeetCoding Challenge with cpp.

January LeetCoding Challenge 1

Description

Plus One

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.

Example 1:

Input: digits = [1,2,3]
Output: [1,2,4]
Explanation: The array represents the integer 123.
Incrementing by one gives 123 + 1 = 124.
Thus, the result should be [1,2,4].

Example 2:

Input: digits = [4,3,2,1]
Output: [4,3,2,2]
Explanation: The array represents the integer 4321.
Incrementing by one gives 4321 + 1 = 4322.
Thus, the result should be [4,3,2,2].

Example 3:

Input: digits = [9]
Output: [1,0]
Explanation: The array represents the integer 9.
Incrementing by one gives 9 + 1 = 10.
Thus, the result should be [1,0].

Constraints:

• 1 <= digits.length <= 100
• 0 <= digits[i] <= 9
• digits does not contain any leading 0's.

Solution

class Solution {
public:
  vector<int> plusOne(vector<int>& digits) {
    int carry = 1;
    for(auto it = digits.rbegin(); carry && it != digits.rend(); ++it) {
      int curVal = *it + carry;
      carry = curVal / 10;
      *it = curVal % 10;
    }
    if(carry == 1) {
      digits.insert(digits.begin(), 1, 1);
    }
    return digits;
  }
};

// Accepted
// 112/112 cases passed (0 ms)
// Your runtime beats 100 % of cpp submissions
// Your memory usage beats 50.17 % of cpp submissions (11.6 MB)