pehla hard and backtracking problem jo acche se samajh aya lol

Author: ChSatyaSavith

1601. Maximum Number of Achievable Transfer Requests.cpp

@@ -0,0 +1,36 @@
+class Solution {
+public:
+    int ans = 0;
+    vector<vector<int>> req;
+
+    void backtrack(int index,int count,vector<int> transfers)
+    {
+        if(index==req.size())
+        {
+            for(int i: transfers)
+            {
+                if(i!=0)
+                {
+                    return;
+                }
+            }
+            ans = max(ans,count);
+            return;
+        }
+
+        transfers[req[index][0]]--;
+        transfers[req[index][1]]++;
+        backtrack(index+1,count+1,transfers);
+        transfers[req[index][0]]++;
+        transfers[req[index][1]]--;
+        backtrack(index+1,count,transfers);
+
+    }
+    int maximumRequests(int n, vector<vector<int>>& requests) 
+    {
+        req = requests;
+        vector<int> transfers(n,0);
+        backtrack(0,0,transfers);
+        return ans;
+    }
+};