Update 445-add-two-numbers-II.js

Author: everthis

445-add-two-numbers-II.js

@@ -1,3 +1,63 @@
+/**
+ * Definition for singly-linked list.
+ * function ListNode(val, next) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.next = (next===undefined ? null : next)
+ * }
+ */
+/**
+ * @param {ListNode} l1
+ * @param {ListNode} l2
+ * @return {ListNode}
+ */
+const addTwoNumbers = function(head1, head2) {
+  const r1 = reverse(head1), r2 = reverse(head2)
+  let l1 = r1, l2 = r2, inc = 0
+  let dummy = new ListNode()
+  let pre = dummy
+  while(l1 || l2) {
+    let val = inc
+    if(l1) {
+      val += l1.val
+      l1 = l1.next
+    }
+    if(l2) {
+      val += l2.val
+      l2 = l2.next
+    }
+    if(val > 9) inc = 1
+    else inc = 0
+    const cur = new ListNode(val % 10)
+    pre.next = cur
+    pre = cur
+  }
+  if (inc) {
+    pre.next = new ListNode(1)
+  }
+  return reverse(dummy.next) 
+};
+
+function reverse(head) {
+  const dummy = new ListNode()
+  dummy.next = head
+  let len = 0, cur = head
+  while(cur) {
+    len++
+    cur = cur.next
+  }
+  let p = dummy, tail = head, tmp = null
+  for(let i = 0; i < len - 1; i++) {
+    tmp = p.next
+    p.next = tail.next
+    tail.next = tail.next.next
+    p.next.next = tmp
+  }
+  return dummy.next
+}
+
+
+// another
+
 /**
  * Definition for singly-linked list.
  * function ListNode(val) {