Adding triplet sum code

DSA_Codesheet/Java/Triplet_Sum.java

@@ -0,0 +1,28 @@
+import java.util.Arrays;
+
+public class Triplet_Sum {
+    public static void main(String[] args) {
+        int[] arr = {1,2,4,3,6};
+        System.out.println(threeSum(arr,10));
+
+    }
+    static boolean threeSum(int[] arr,int x){
+        Arrays.sort(arr);
+        int n = arr.length;
+        for (int i = 0; i < n; i++) {
+            int j = i+1;
+            int k = arr.length-1;
+            while (j<k){
+                int sum = arr[i]+arr[j]+arr[k];
+                if(sum==x){
+                    return true;
+                } else if (sum<x) {
+                    j++;
+                }else{
+                    k--;
+                }
+            }
+        }
+        return false;
+    }
+}