Added reorderList solution

Author: nhistory

reorder-list/nhistory.js

@@ -0,0 +1,26 @@
+var reorderList = function (head) {
+  if (!head) return;
+  // Create new arr to return result and current head
+  let arr = [];
+  let curr = head;
+  // Make list array that has every values from linked list
+  let list = [];
+  while (curr) {
+    list.push(curr.val);
+    curr = curr.next;
+  }
+  // Iterate list array if i%2 === 0 then curr.val = list[Math.floor(i / 2)]
+  // If i%2 !== 0 them curr.val = list[list.length - Math.floor((i + 1) / 2)]
+  curr = head;
+  for (let i = 0; i < list.length; i++) {
+    if (i % 2 === 0) {
+      curr.val = list[Math.floor(i / 2)];
+    } else {
+      curr.val = list[list.length - Math.floor((i + 1) / 2)];
+    }
+    curr = curr.next;
+  }
+};
+
+// TC: O(n)
+// SC: O(n)