Merge pull request #588 from bacecek/bacecek_brackets_in_java

Solve simple balanced brackets task.

Author: t2013anurag

brackets/README.md

@@ -0,0 +1,8 @@
+## Balanced Brackets
+
+### Description
+Given a sequence consisting of brackets, determine whether the expression is balanced. A sequence of brackets is balanced if every open bracket can be paired uniquely with a closed bracket that occurs after the former. Also, the interval between them must be balanced. You will be given three types of brackets: (, {, [.
+
+`([{}])` - this is balanced brackets
+
+`([{]})` - this is not balanced brackets

brackets/java/brackets.java

@@ -0,0 +1,34 @@
+import java.util.Stack;
+
+public class brackets {
+
+    public static void main(String[] args) {
+        System.out.println(solve("[{()}[]({[]})]")); // yes
+        System.out.println(solve("()()")); // yes
+        System.out.println(solve("((()[]")); // no
+    }
+
+    public static String solve(String s) {
+        Stack<Character> stack = new Stack<>();
+        for (char c : s.toCharArray()) {
+            if (c == '(' || c == '[' || c == '{') stack.push(c);
+            else {
+                if (stack.empty()) return "no";
+                char p = stack.pop();
+                if (c == ')') {
+                    if (p != '(') return "no";
+                    else continue;
+                }
+                if (c == ']') {
+                    if (p != '[') return "no";
+                    else continue;
+                }
+                if (c == '}') {
+                    if (p != '{') return "no";
+                }
+            }
+        }
+        return stack.empty() ? "yes" : "no";
+    }
+
+}