134. Gas Station (Imp. Queue qs.)

One of Important question from Queue

Author: SjxSubham

134. Gas Station

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+//T.C - o(n)
+//S.C - o(1)
+
+class Solution {
+public:
+    int canCompleteCircuit(vector<int>& gas, vector<int>& cost) {
+        //petrol ki kitni kami hai yani Ghat ti
+        int deficit =0;
+        //petrol kitna bacha hua hai
+        int balance =0;
+        ///circuit kha se suru kre 
+        int start =0;
+        for(int i =0;i<gas.size();i++){
+            balance += gas[i] - cost[i];
+            if(balance < 0){
+                deficit += balance; // yahi par galti hoti hai...deficit ko increment krna padega   // or deficit += abs(balance);
+                start = i+1;
+                balance =0;
+            }
+        }
+        if(deficit + balance >=0){   // or if(balance >= deficit)
+            return start;
+        }
+        else{
+            return -1;
+        }
+    }
+};
+
+