Updated jump game 2

Author: FreeTymeKiyan

Hard/JumpGame2.java

@@ -13,7 +13,7 @@
  * The minimum number of jumps to reach the last index is 2. (Jump 1 step from
  * index 0 to 1, then 3 steps to the last index.)
  * 
- * Tags: Array, Greedy
+ * Tags: Array, Greedy, DP
  */
 class JumpGame2 {
     public static void main(String[] args) {
@@ -22,22 +22,24 @@ public static void main(String[] args) {
 
     /**
      * Use last to store how far we already can reach
+     * Compare i with last
      * If we run out of it, update and add 1 more step to result
      * Return if last is already bigger than or equal to the length
      * Use cur to store how far we can reach for the next step
      */
     public int jump(int[] A) {
-        int res = 0;
+        int step = 0;
         int last = 0; // how far we already can reach
         int cur = 0; // how far can we reach for next step
+        
         for (int i = 0; i < A.length; i++) {
-            if (i > last) { // run out of we can reach
+            if (i > last) { // run out of we can reach, need one more step
                 last = cur;
-                res++;
-                if (last >= A.length) return res;
+                step++;
+                if (last >= A.length) return step;
             }
             cur = Math.max(cur, i + A[i]);
         }
-        return res;
+        return step;
     }
-}
+}