Day 20 - LeetCode 66. Plus One

LeetCode 66. Plus One

題目

Given a non-negative number represented as an array of digits, plus one to the number.
The digits are stored such that the most significant digit is at the head of the list.

翻譯

給一包含非數整數的陣列，其中每一個值代表該位數的值，對這個陣列加1。
範例：
19 = [1,9] ， 19+1 = 20 = [2,0]。

想法

從個位數開始跑, 進位就加一

詳細參閱

https://skyyen999.gitbooks.io/-leetcode-with-javascript/content/questions/66md.html

https://discuss.leetcode.com/topic/82381/java-solution-0ms

---

Code

/**
 * @param {number[]} digits
 * @return {number[]}
 */
var plusOne = function(digits) {

    let carry = 0;

    for ( let i = digits.length - 1; i >= 0; i-- ) {

        digits[i] = digits[i] + carry;
        //個位數＋1
        if ( i == digits.length - 1 ) {
            digits[i] = digits[i] + 1;
        }
        //10 就進位
        if ( digits[i] == 10 ) {
            digits[i] = 0;
            carry = 1;
        } else {
            carry = 0;
        }
    }
    //最後如需要補進位時
    if ( carry == 1 ) {
        digits.unshift(carry);
    }

    return digits;
};

/**
 * @param {number[]} digits
 * @return {number[]}
 */
var plusOne = function(digits) {

    for ( let i = digits.length - 1; i >= 0; i-- ) {
        if ( digits[i] < 9 ) {
            digits[i]++;
            return digits;
        } else {
            digits[i] = 0;
        }
    }
    digits.unshift(1)

    return digits;
};

Run