Create: 0946-validate-stack-sequences.cpp

winfred-lu · winfred-lu · commit 9065e70b1d21 · 2024-01-17T16:09:33.000+08:00
diff --git a/cpp/0946-validate-stack-sequences.cpp b/cpp/0946-validate-stack-sequences.cpp
@@ -0,0 +1,25 @@
+/*
+  Given two integer arrays pushed and popped each with distinct values,
+  return true if this could have been the result of a sequence of push
+  and pop operations on an initially empty stack, or false otherwise.
+
+  Time: O(n)
+  Space: O(n)
+*/
+
+class Solution {
+public:
+    bool validateStackSequences(vector<int>& pushed, vector<int>& popped) {
+        stack<int> stk;
+        int i = 0;
+        for (int num : pushed) {
+            stk.push(num);
+            while (!stk.empty() && stk.top() == popped[i]) {
+                stk.pop();
+                ++i;
+            }
+        }
+        return stk.empty();
+    }
+};
+
