Refactored Validate Stack Sequences.java

varunu28 · web-flow · commit 53703d4f8e20 · 2021-02-26T12:39:25.000-08:00
diff --git a/Medium/Validate Stack Sequences.java b/Medium/Validate Stack Sequences.java
@@ -1,28 +1,22 @@
 class Solution {
   public boolean validateStackSequences(int[] pushed, int[] popped) {
-    int pushStart = 0;
-    int popStart = 0;
     Stack<Integer> stack = new Stack<>();
-    while (pushStart < pushed.length && popStart < popped.length) {
-      if (stack.isEmpty()) {
-        stack.push(pushed[pushStart++]);
-      }
-      else {
-        if (stack.peek() == popped[popStart]) {
-          stack.pop();
-          popStart++;
-        }
-        else {
-          stack.push(pushed[pushStart++]);
-        }
+    int pushedIdx = 0;
+    int poppedIdx = 0;
+    while (pushedIdx < pushed.length && poppedIdx < popped.length) {
+      if (!stack.isEmpty() && stack.peek() == popped[poppedIdx]) {
+        stack.pop();
+        poppedIdx++;
+      } else {
+        stack.push(pushed[pushedIdx++]);
       }
     }
-    while (popStart < popped.length) {
-      if (stack.peek() != popped[popStart]) {
+    while (poppedIdx < popped.length) {
+      if (stack.peek() != popped[poppedIdx]) {
         return false;
       }
+      poppedIdx++;
       stack.pop();
-      popStart++;
     }
     return true;
   }
