add 2116

Author: fishercoder1534

README.md

@@ -8,6 +8,7 @@ _If you like this project, please leave me a star._ ★
 
 |  #  |      Title     |   Solutions   | Video  | Difficulty  | Tag                  
 |-----|----------------|---------------|--------|-------------|-------------
+|2116|[Check if a Parentheses String Can Be Valid](https://leetcode.com/problems/check-if-a-parentheses-string-can-be-valid/)|[Java](../master/src/main/java/com/fishercoder/solutions/_2116.java) ||Medium||
 |2114|[Maximum Number of Words Found in Sentences](https://leetcode.com/problems/maximum-number-of-words-found-in-sentences/)|[Java](../master/src/main/java/com/fishercoder/solutions/_2114.java) ||Easy||
 |2110|[Number of Smooth Descent Periods of a Stock](https://leetcode.com/problems/number-of-smooth-descent-periods-of-a-stock/)|[Java](../master/src/main/java/com/fishercoder/solutions/_2110.java) ||Medium||
 |2109|[Adding Spaces to a String](https://leetcode.com/problems/adding-spaces-to-a-string/)|[Java](../master/src/main/java/com/fishercoder/solutions/_2109.java) ||Medium||

src/main/java/com/fishercoder/solutions/_2116.java

@@ -0,0 +1,27 @@
+package com.fishercoder.solutions;
+
+public class _2116 {
+    public static class Solution1 {
+        /**
+         * credit: https://leetcode.com/problems/check-if-a-parentheses-string-can-be-valid/discuss/1646594/Left-to-right-and-right-to-left
+         */
+        public boolean canBeValid(String s, String locked) {
+            return s.length() % 2 == 0 && valid(s, locked, '(') && valid(s, locked, ')');
+        }
+
+        private boolean valid(String s, String locked, char op) {
+            int balance = 0;
+            int wildcards = 0;
+            int direction = op == '(' ? 1 : -1;
+            int start = op == '(' ? 0 : s.length() - 1;
+            for (int i = start; i < s.length() && i >= 0 && balance + wildcards >= 0; i += direction) {
+                if (locked.charAt(i) == '1') {
+                    balance += s.charAt(i) == op ? 1 : -1;
+                } else {
+                    wildcards++;
+                }
+            }
+            return wildcards + balance >= 0 && balance <= wildcards;
+        }
+    }
+}

src/test/java/com/fishercoder/_2116Test.java

@@ -0,0 +1,42 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._2116;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class _2116Test {
+    private static _2116.Solution1 solution1;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _2116.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        assertEquals(true, solution1.canBeValid("))()))", "010100"));
+    }
+
+    @Test
+    public void test2() {
+        assertEquals(true, solution1.canBeValid("()()", "0000"));
+    }
+
+    @Test
+    public void test3() {
+        assertEquals(false, solution1.canBeValid(")", "0"));
+    }
+
+    @Test
+    public void test4() {
+        assertEquals(true, solution1.canBeValid(")(", "00"));
+    }
+
+    @Test
+    public void test5() {
+        assertEquals(false, solution1.canBeValid("())(()(()(())()())(())((())(()())((())))))(((((((())(()))))(", "100011110110011011010111100111011101111110000101001101001111"));
+    }
+
+}