Swap Node Pairs in List solution

Author: joshguha

23-swapNodePairs.js

@@ -0,0 +1,54 @@
+/**
+ * Definition for singly-linked list.
+  function ListNode(val, next) {
+      this.val = (val===undefined ? 0 : val)
+      this.next = (next===undefined ? null : next)
+  }
+ */
+/**
+ * @param {ListNode} head
+ * @return {ListNode}
+ */
+var swapPairs = function (head) {
+    if (head === null) {
+        return null;
+    }
+
+    let result = [];
+    let thisNode = head;
+    while (thisNode !== null) {
+        result.push(thisNode);
+        thisNode = thisNode.next;
+    }
+
+    for (let i = 1; i < result.length; i += 2) {
+        console.log("i", i);
+        let temp = result[i - 1];
+        result[i - 1] = result[i];
+        result[i] = temp;
+    }
+
+    for (let i = 0; i < result.length; i++) {
+        if (i === result.length) {
+            result[i].next = null;
+        } else {
+            result[i].next = result[i + 1];
+        }
+    }
+
+    return result[0];
+};
+
+function ListNode(val, next) {
+    this.val = val === undefined ? 0 : val;
+    this.next = next === undefined ? null : next;
+}
+
+f = new ListNode(9);
+e = new ListNode(8, f);
+d = new ListNode(7, e);
+c = new ListNode(6, d);
+b = new ListNode(5, c);
+a = new ListNode(4, b);
+
+console.log(swapPairs(a));