solved on 13/12/2023

Author: Priyanshu-Ganatra

LC_101_GasStation.cpp

@@ -0,0 +1,42 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+// tc : O(n) sc : O(1)
+int canCompleteCircuit(vector<int> &gas, vector<int> &cost)
+{
+    int deficit = 0; // deficit is the amount of gas we need to reach the next station
+    int balance = 0; // balance is the amount of gas we have in our tank which is calculated by subtracting the cost from the gas
+    // index of the starting point
+    int start = 0;
+
+    for (int i = 0; i < gas.size(); i++)
+    {
+        int temp = balance + gas[i] - cost[i]; // balance after reaching the next station from the current station, if negative we can't reach the next station
+        if (temp < 0)
+        {
+            // if balance is negative, we can't start from this station
+            // as we will run out of gas before reaching the next station
+            // so we start from the next station
+            start = i + 1;
+            // deficit is the amount of gas we need to reach the next station
+            deficit += abs(temp);
+            // reset balance
+            balance = 0;
+        }
+        else
+        {   
+            balance = temp;
+        }
+    }
+    // if the total balance is less than the total deficit, we can't complete the circuit
+    // else we can start from the start index
+    return (balance - deficit >= 0) ? start : -1;
+}
+
+int main()
+{
+    vector<int> gas = {1, 2, 3, 4, 5};
+    vector<int> cost = {3, 4, 5, 1, 2};
+    cout << canCompleteCircuit(gas, cost) << endl;
+    return 0;
+}