Plus One

Author: w2xi

README.md

@@ -8,6 +8,7 @@
 |9|[回文数](https://leetcode-cn.com/problems/palindrome-number/)|[JavaScript](./algorithms/palindrome-number.js)|Easy|
 |14|[最长公共前缀](https://leetcode-cn.com/problems/longest-common-prefix/)|[JavaScript](./algorithms/longest-common-prefix.js)|Easy|
 |21|[合并两个有序链表](https://leetcode-cn.com/problems/merge-two-sorted-lists/)|[JavaScript](./algorithms/merge-two-sorted-lists.js)|Easy|
+|66|[加一](https://leetcode-cn.com/problems/plus-one/)|[JavaScript](./algorithms/plus-one.js)|Easy|
 |136|[只出现一次的数字](https://leetcode-cn.com/problems/single-number/)|[JavaScript](./algorithms/single-number.js)|Easy|
 |189|[轮转数组](https://leetcode-cn.com/problems/rotate-array/)|[JavaScript](./algorithms/rotate-array.js)|Medium|
 |344|[反转字符串](https://leetcode-cn.com/problems/reverse-string/)|[JavaScript](./algorithms/reverse-string.js)|Easy|

algorithms/plus-one.js

@@ -0,0 +1,34 @@
+// 方法：进位
+// 解题思路来自：两数相加
+// Reference: https://leetcode-cn.com/problems/add-two-numbers/
+
+/**
+ * 加一
+ * @param {number[]} digits
+ * @return {number[]}
+ */
+var plusOne = function (digits) {
+  const lastIndex = digits.length - 1;
+  // 进位
+  let curry = 0;
+  let arr = [];
+
+  for (let i = lastIndex; i >= 0; i--) {
+    let current = digits[i];
+
+    if (i === lastIndex) {
+      current++;
+    }
+    const sum = current + curry;
+    curry = Math.floor(sum / 10);
+    current = sum % 10;
+
+    arr.unshift(current);
+  }
+
+  if (curry) {
+    arr.unshift(curry);
+  }
+
+  return arr;
+};