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Javascript(leetcode#67) Add Binary

發表於 更新於 分類於 ， Disqus：

Difficult:Easy

題目

Given two binary strings a and b, return their sum as a binary string.

翻譯

給定兩個二進製字符串 a 和 b，將它們的和作為二進製字符串返回。

範例

Example 1

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Input: a = "11", b = "1"
Output: "100"

Example 2

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Input: a = "1010", b = "1011"
Output: "10101"

解題思路

1.從最後開始計算超過2進位

Solution

Code 1 :

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var addBinary = function (a, b) {

    let len = Math.max(a.length - 1, b.length - 1);
    let lens = 0;
    let str = [];
    let n = 0;
    while (lens <= len || n == 1) {
        let aval = parseInt(a[a.length - 1 - lens]) || 0;
        let bval = parseInt(b[b.length - 1 - lens]) || 0;
        let sum = aval + bval + n;
        if (sum > 1) {
            n = 1;
            sum %= 2;
        } else {
            n = 0;
        }
        str.unshift(sum);
        lens++;
    }
    return str.join("");
};