Create Gas_Station.cc

New problem of leetcode.

Author: iphkwan

Gas_Station.cc

@@ -0,0 +1,25 @@
+class Solution {
+public:
+    int canCompleteCircuit(vector<int> &gas, vector<int> &cost) {
+        // Note: The Solution object is instantiated only once and is reused by each test case.
+        if (gas.size() == 0)
+            return -1;
+        int count = 1, ret = 0, remind_gas = gas[0], tot = 0;
+        while (count <= gas.size()) {
+            if (remind_gas >= cost[(ret + count - 1) % gas.size()]) {
+                remind_gas += (gas[(ret + count) % gas.size()] - cost[(ret + count - 1) % gas.size()]);
+                count++;
+            } else {
+                remind_gas = gas[(ret + count) % gas.size()];
+                ret = (ret + count) % gas.size();
+                count = 1;
+            }
+            tot++;
+            if (tot > 2 * gas.size()) {
+                ret = -1;
+                break;
+            } 
+        }
+        return ret;
+    }
+};