合并链表代码

Author: wangjieCode

main.js

@@ -1 +1,93 @@
-console.log("222")
+function ListNode(val) {
+    this.val = val;
+    this.next = null;
+}
+
+const a = new ListNode(1)
+const b = new ListNode(2)
+const c = new ListNode(4)
+a.next = b
+b.next = c
+const d = new ListNode(1)
+const e = new ListNode(3)
+const f = new ListNode(4)
+d.next = e
+e.next = f
+
+function bianli(root, vals = []) {
+    while (root && root !== null) {
+        vals.push(root.val)
+        root = root.next
+    }
+    return vals
+}
+// bianli(a)
+// bianli(d)
+
+/** 迭代法
+ * @param {ListNode} l1
+ * @param {ListNode} l2
+ * @return {ListNode}
+ */
+var mergeTwoLists = function (l1, l2) {
+    let res = new ListNode();
+    let root = res
+    while (l1 !== null && l2 !== null) {
+        if (l1.val <= l2.val) {
+            root.next = l1;
+            l1 = l1.next;
+        } else {
+            root.next = l2
+            l2 = l2.next;
+        }
+        root = root.next
+    }
+    if (l1 != null) {
+        root.next = l1;
+    }
+
+    if (l2 != null) {
+        root.next = l2;
+    }
+    return res.next
+};
+
+/**转化数组法
+ * @param {ListNode} l1
+ * @param {ListNode} l2
+ * @return {ListNode}
+ */
+var mergeTwoLists2 = function (l1, l2) {
+    if (l1 == null && l2 == null) return l1
+    const l1res = bianli(l1)
+    const l2res = bianli(l2)
+    const resData = [...l1res, ...l2res].sort((a, b) => a - b)
+    let root = new ListNode(resData[0]);
+    let res = root;
+    for (let i = 1; i < resData.length; i++) {
+        res.next = new ListNode(resData[i])
+        res = res.next;
+    }
+    return root
+};
+
+
+/**递归
+ * @param {ListNode} l1
+ * @param {ListNode} l2
+ * @return {ListNode}
+ */
+var mergeTwoLists3 = function (l1, l2) {
+    if (l1 == null) {
+        return l2;
+    } else if (l2 == null) {
+        return l1;
+    } else if (l1.val < l2.val) {
+        l1.next = mergeTwoLists(l1.next, l2);
+        return l1;
+    } else {
+        l2.next = mergeTwoLists(l1, l2.next);
+        return l2;
+    }
+};
+console.log(bianli(mergeTwoLists3(a, d)))