Combinations of n-pairs of parentheses.

src/TechInterview/Parenthesis.java

@@ -0,0 +1,33 @@
+package TechInterview;
+
+public class Parenthesis {
+
+//    Implement an algorithm to print all valid (e.g., properly opened and closed) combinations
+//    of n-pairs of parentheses.
+
+    public static void parenthesis(int open, int closed, String answer) {
+
+        if (open == 0 && closed == 0) {
+            System.out.printf("%s\n", answer);
+        }
+        if (open > 0) {
+            parenthesis(open - 1, closed + 1, answer + "(");
+        }
+        if (closed > 0) {
+            parenthesis(open, closed - 1, answer + ")");
+        }
+
+    }
+
+    public static void solution(int n) {
+
+        parenthesis(n, 0, "");
+
+    }
+
+    public static void main(String[] args) {
+
+        solution(3);
+
+    }
+}