From 6531d1a35f63de596a1f09ab9f5654dd85fa2881 Mon Sep 17 00:00:00 2001
From: Matej Focko <me@mfocko.xyz>
Date: Tue, 10 Sep 2024 12:38:26 +0200
Subject: [PATCH] =?UTF-8?q?java:=20add=20=C2=AB32.=20Longest=20Valid=20Par?=
 =?UTF-8?q?entheses=C2=BB?=
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Signed-off-by: Matej Focko <me@mfocko.xyz>
---
 java/longest-valid-parentheses.java | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 java/longest-valid-parentheses.java

diff --git a/java/longest-valid-parentheses.java b/java/longest-valid-parentheses.java
new file mode 100644
index 0000000..0e70410
--- /dev/null
+++ b/java/longest-valid-parentheses.java
@@ -0,0 +1,24 @@
+import java.util.Stack;
+
+class Solution {
+  public int longestValidParentheses(String s) {
+    var longest = 0;
+    var indices = new Stack<Integer>();
+
+    indices.push(-1);
+    for (var i = 0; i < s.length(); ++i) {
+      if (s.charAt(i) == '(') {
+        indices.push(i);
+      } else {
+        indices.pop();
+        if (indices.isEmpty()) {
+          indices.push(i);
+        } else {
+          longest = Math.max(longest, i - indices.peek());
+        }
+      }
+    }
+
+    return longest;
+  }
+}