0066. Plus One (E)

Plus One (E)

题目

Given a non-empty array of digits representing a non-negative integer, plus one to the integer.

The digits are stored such that the most significant digit is at the head of the list, and each element in the array contain a single digit.

You may assume the integer does not contain any leading zero, except the number 0 itself.

Example 1:

Input: [1,2,3]
Output: [1,2,4]
Explanation: The array represents the integer 123.

Example 2:

Input: [4,3,2,1]
Output: [4,3,2,2]
Explanation: The array represents the integer 4321.

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题意

将一个整数各位存放到数组中，输出加1后的整数(依然用数组表示)。

思路

注意进位即可。

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代码实现

Java

class Solution {
    public int[] plusOne(int[] digits) {
        int i = digits.length - 1;
        digits[i]++;
        int carry = digits[i] / 10;
        digits[i] = digits[i] % 10;
        // 需要进位则一直向前
        while (carry != 0 && i >= 1) {
            i--;
            digits[i] = digits[i] + carry;
            carry = digits[i] / 10;
            digits[i] = digits[i] % 10;
        }
        // 仍需要进位，说明需要新增一位数
        if (carry != 0) {
            int[] temp = new int[digits.length + 1];
            for (int j = 1; j < temp.length; j++) {
                temp[j] = digits[j - 1];
            }
            temp[0] = carry;
            digits = temp;
        }
        return digits;
    }
}

JavaScript

/**
 * @param {number[]} digits
 * @return {number[]}
 */
var plusOne = function (digits) {
  let i = digits.length - 1
  let carry = 1

  while (i >= 0 && carry > 0) {
    digits[i] += carry
    carry = Math.trunc(digits[i] / 10)
    digits[i] %= 10
    i--
  }

  if (carry > 0) {
    digits.splice(0, 0, carry)
  }

  return digits
}