Adding java solution file for 1601 question

Maximum Number of Achievable Transfer Requests

Author: coderaky

src/main/java/com/fishercoder/solutions/_1601.java

@@ -0,0 +1,29 @@
+class Solution {
+    int max = 0;
+    public int maximumRequests(int n, int[][] requests) {
+        helper(requests, 0, new int[n], 0);
+        return max;
+    }
+    
+    private void helper(int[][] requests, int index, int[] count, int num) {
+        // Traverse all n buildings to see if they are all 0. (means balanced)
+        if (index == requests.length) {
+            for (int i : count) {
+                if (0 != i) {
+                    return;
+                }
+            }
+            max = Math.max(max, num);
+            return;
+        }
+		// Choose this request
+        count[requests[index][0]]++;
+        count[requests[index][1]]--;
+        helper(requests, index + 1, count, num + 1);
+        count[requests[index][0]]--;
+        count[requests[index][1]]++;
+        
+		// Not Choose the request
+        helper(requests, index + 1, count, num);
+    }
+}