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0134-gas-station/0134-gas-station.cpp

@@ -1,24 +1,40 @@
 class Solution {
 public:
     int canCompleteCircuit(vector<int>& gas, vector<int>& cost) {
+
         int n=gas.size();
-        int total_gas=0,total_cost=0;
-        int curr_gas=0, starting_point=0;
-        for(int i=0;i<n;i++)
+        int ans=0;
+        int amt=0;
+        int fnt=0;
+        int cnt=0;
+        if(n==1)
         {
-            //these two variable are to check if no case is possible
-            total_gas+=gas[i];
-            total_cost+=cost[i];
-            //for checking the total present gas at index i
-            curr_gas+=gas[i]-cost[i];
-            if(curr_gas<0)
+            if(gas[0]-cost[0]>=0)return 0;
+            else return -1;
+        }
+        for(int i=0;i<n;i=(i+1)%n)
+        {
+            if(cnt==2*n)break;
+            if(fnt==0)ans=i;
+            cout<<i<<" ";
+            if(i==ans && fnt==1)return i;
+
+            if(amt+gas[i]>=cost[i])
+            {
+                amt+=gas[i];
+                amt-=cost[i];
+            }
+            else if(amt+gas[i]<cost[i])
             {
-               //there is a breakdown....so we will start from next point or index
-                starting_point=i+1;
-                //reset our fuel 
-                curr_gas=0;
+                amt=0;
+                ans=(i+1)%n;
+                fnt=0;
             }
+
+            if(i==ans)fnt=1;
+            cnt++;
         }
-        return (total_gas<total_cost)?-1:starting_point;     
+        return -1;
+
     }
 };