balanced bracket

src/main/java/data/structure/stack/Brackets.java

@@ -0,0 +1,41 @@
+package data.structure.stack;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Stack;
+
+/**
+ * Check if string is a balanced bracket or not. e.g (([{}])) is balanced, (([{])) it is not.
+ * That's a stack data structure solution o(n)
+ */
+public class Brackets {
+
+
+    public boolean balancedBracket(String s) {
+
+        // ([])
+        Map<Character, Character> openClosedKeyValue = new HashMap<>();
+        openClosedKeyValue.put('(', ')');
+        openClosedKeyValue.put('{', '}');
+        openClosedKeyValue.put('[', ']');
+
+        Stack<Character> stack = new Stack<>();
+        var stringArr = s.toCharArray();
+        for (char c : stringArr) {
+
+            if (openClosedKeyValue.containsKey(c)) { // open
+
+                stack.push(c);
+            } else { // closed
+
+                var lastOpenedBracket = stack.pop();
+                if (!openClosedKeyValue.get(lastOpenedBracket).equals(c)) // if char is not corresponding to the closed bracket of the last opened bracket
+                    return false;
+
+            }
+        }
+
+        return stack.isEmpty();
+    }
+
+}

src/test/java/data/structure/stack/BracketsTest.java

@@ -0,0 +1,17 @@
+package data.structure.stack;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class BracketsTest {
+
+    @Test
+    public void test() {
+        Brackets brackets = new Brackets();
+        Assertions.assertTrue(brackets.balancedBracket("(([{}]))"));
+        Assertions.assertFalse(brackets.balancedBracket("(([{]))"));
+        Assertions.assertFalse(brackets.balancedBracket("(([{}]{)"));
+
+    }
+
+}