66. Plus One

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66. Plus One

Description

You are given a large integer represented as an integer array digits, where each digits[i] is the i^th 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:

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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:

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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:

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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.

Hints/Notes

Solution

Language: C++

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class Solution {
public:
    vector<int> plusOne(vector<int>& digits) {
        int n = digits.size(), carry = 1;
        for (int i = n - 1; i >= 0; i--) {
            digits[i] += carry;
            if (digits[i] < 10) {
                carry = 0;
                break;
            }
            digits[i] = 0;
        }
        if (carry) {
            digits.insert(digits.begin(), 1);
        }
        return digits;
    }
};