Add week 12 solutions: jumpGame

Author: yolophg

jump-game/yolophg.js

@@ -0,0 +1,19 @@
+// Time Complexity: O(n)
+// Space Complexity: O(1)
+
+var canJump = function (nums) {
+  // start from the last position
+  let lastPos = nums.length - 1;
+
+  // traverse the array from the end to the start
+  for (let i = nums.length - 2; i >= 0; i--) {
+    // if can jump from the current position to the lastPos or beyond
+    if (i + nums[i] >= lastPos) {
+      // move the lastPos to the current position
+      lastPos = i;
+    }
+  }
+
+  // if have moved lastPos to the start, can reach the end
+  return lastPos === 0;
+};