balanced paranthesis implemented

Author: saihariG

Stack/BalancedParanthesisUsingStack.java

@@ -1,10 +1,74 @@
 package Stack;
 
 
+import java.util.Stack;
+
 public class BalancedParanthesisUsingStack {
 
+    /***
+     * Algorithm :
+     * @return boolean
+     * 1. Define a Stack
+     * 2. scan the String and parse the brackets
+     * 3. if the bracket is left bracket it means another bracket suppose to
+     *    complete it. keep pushing into the stack
+     *
+     * 4. if it's a right bracket check if the top item in the stack equals its reverseBracket
+     * 5. if it is not equal or if stack is empty , it means they are not balanced
+     * 6. After parsing , if the stack is empty , then brackets are balanced
+     */
+    public static boolean isBracketBalanced(String str) {
+
+        Stack<Character> stack = new Stack<>();
+        char[] bracket = str.toCharArray();
+
+        for(char ch : bracket) {
+
+            char reverseBracket = getReverseBracket(ch);
+            if (ch == '{' || ch == '[' || ch == '(') {
+                stack.push(ch);
+            }
+            else if(stack.isEmpty() || stack.pop() != reverseBracket) {
+                return false;
+            }
+        }
+
+        return stack.isEmpty();
+    }
+
+    public static char getReverseBracket(char ch) {
+        if(ch == '{') {
+            return '}';
+        }
+        else if(ch == '[') {
+            return ']';
+        }
+        else if(ch == '(') {
+            return ')';
+        }
+        else if(ch == '}') {
+            return '{';
+        }
+        else if(ch == ']') {
+            return '[';
+        }
+        else {
+            return '(';
+        }
+    }
+
     public static void main(String[] args) {
-        // yet to implement
+
+        String test1 = "{([])}";
+        String test2 = "{([)}";
+        String test3 = "{([])";
+        String test4 = "{[()]}";
+
+        System.out.println(isBracketBalanced(test1)); // true
+        System.out.println(isBracketBalanced(test2)); // false
+        System.out.println(isBracketBalanced(test3)); // false
+        System.out.println(isBracketBalanced(test4)); // true
+
     }
 
-}
+}