added canCompleteCircuit

canCompleteCircuit/src/canCompleteCircuit.hpp

@@ -0,0 +1,16 @@
+#include <vector>
+
+inline int canCompleteCircuit(std::vector<int> &gas, std::vector<int> &cost) {
+  int total_tank = 0;
+  int curr_tank = 0;
+  int start = 0;
+  for (int i = 0; i < int(gas.size()); i++) {
+    total_tank += gas[i] - cost[i];
+    curr_tank += gas[i] - cost[i];
+    if (curr_tank < 0) {
+      start = i + 1;
+      curr_tank = 0;
+    }
+  }
+  return total_tank >= 0 ? start : -1;
+}

canCompleteCircuit/src/main.cpp

@@ -0,0 +1,16 @@
+#include <cassert>
+#include <vector>
+#include "canCompleteCircuit.hpp"
+
+int main() {
+  std::vector<int> gas = {1, 2, 3, 4, 5};
+  std::vector<int> cost = {3, 4, 5, 1, 2};
+  int output = canCompleteCircuit(gas, cost);
+  assert(output == 3);
+
+  gas = {2, 3, 4};
+  cost = {3, 4, 3};
+  output = canCompleteCircuit(gas, cost);
+  assert(output == -1);
+  return 0;
+}