2022-09-08 update: added "Valid Parenthesis String" (#87)

Author: fartem

src/main/java/com/smlnskgmail/jaman/leetcodejava/medium/ValidParenthesisString.java

@@ -0,0 +1,27 @@
+package com.smlnskgmail.jaman.leetcodejava.medium;
+
+// https://leetcode.com/problems/valid-parenthesis-string/
+public class ValidParenthesisString {
+
+    private final String input;
+
+    public ValidParenthesisString(String input) {
+        this.input = input;
+    }
+
+    public boolean solution() {
+        int l = 0;
+        int h = 0;
+        for (int i = 0; i < input.length(); i++) {
+            char c = input.charAt(i);
+            l += c == '(' ? 1 : -1;
+            h += c != ')' ? 1 : -1;
+            if (h < 0) {
+                break;
+            }
+            l = Math.max(l, 0);
+        }
+        return l == 0;
+    }
+
+}

src/test/java/com/smlnskgmail/jaman/leetcodejava/medium/ValidParenthesisStringTest.java

@@ -0,0 +1,14 @@
+package com.smlnskgmail.jaman.leetcodejava.medium;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertTrue;
+
+public class ValidParenthesisStringTest {
+
+    @Test
+    public void defaultTest() {
+        assertTrue(new ValidParenthesisString("()").solution());
+    }
+
+}