Javascript(leetcode#66) Plus One

Difficult:Easy

題目

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.

翻譯

給定一個表示為整數數組digits 的大整數，其中每個digits[i] 是整數的第i 個數字。數字按從左到右的順序從最高有效到最低有效排序。大整數不包含任何前導 0。

將大整數加一併返回結果數字數組。

範例

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].

解題思路

1.從最後開始計算超過10進位

Solution

Code 1 :

var plusOne = function(digits) {
    let end=true;
    let len=digits.length-1;
    while(end){
        let d=digits[len]+1;
        if(d>9){
            digits[len]=d%10;
            len--;
            if(len<0){
                digits.unshift(1);
                end=false;
            }
        }else{
            digits[len]=d;
            end=false;
        }
    }
    return digits;
};