Add Two Numbers

Author: tanjiasheng

Add Two Numbers/index.js

@@ -0,0 +1,53 @@
+/**
+ * Definition for singly-linked list.
+ * function ListNode(val) {
+ *     this.val = val;
+ *     this.next = null;
+ * }
+ */
+/**
+ * @param {ListNode} l1
+ * @param {ListNode} l2
+ * @return {ListNode}
+ */
+var addTwoNumbers = function (l1, l2, res = [0]) {
+    if (l1 === null && l2 === null) {
+        return res[res.length - 1] === 0
+            ? res.slice(0, res.length - 1)
+            : res
+    }
+
+    let l1Val, l2Val, l1Next, l2Next;
+
+    if (l1 === null) {
+        l1Val = 0
+        l1Next = null
+    } else {
+        l1Val = l1.val
+        l1Next = l1.next
+    }
+    if (l2 === null) {
+        l2Val = 0
+        l2Next = null
+    } else {
+        l2Val = l2.val
+        l2Next = l2.next
+    }
+
+    const curRes = l1Val + l2Val + res[res.length - 1]
+    res.splice(
+        res.length - 1,
+        res.length,
+        ...(String(curRes >= 10 ? curRes : `0${curRes}`)
+            .split('')
+            .reverse()
+            .map(i => Number(i))
+        )
+    )
+
+    return addTwoNumbers(
+        l1Next,
+        l2Next,
+        res
+    )
+};

Add Two Numbers/readme.md

@@ -0,0 +1 @@
+和笔算加法的逻辑差不多，给方法添加第三个参数，用以传入上一位的相加结果，递归调用方法，每次拿到当前的数字相加，把结果append进上次的相加结果中，append的同时需要处理上一位的进位。

Two Sum/index.js

@@ -4,9 +4,9 @@
  * @return {number[]}
  */
 var twoSum = function(nums, target) {
-    for(let i = 0; i < nums.length; i++) {
+    for (let i = 0; i < nums.length; i++) {
         const j = nums.indexOf(target - nums[i])
-        if(~j && j !== i) {
+        if (~j && j !== i) {
             return [i, j]
         }
     }