【題目敘述】https://leetcode.com/problems/gas-station/
class Solution {
public:
int canCompleteCircuit(vector<int>& gas, vector<int>& cost) {
int sz = cost.size();
for (int i = 0; i < sz; i++){
cost[i] = gas[i]-cost[i];
}
int idx = 0, mn = cost[0], tot = 0;
for (int i = 0; i < sz; i++){
tot += cost[i];
if (tot < mn){
mn = tot;
idx = i;
}
}
int now;
bool flag = true;
tot = 0;
for (int i = 0; i < sz; i++){
now = (i + idx + 1) % sz;
tot += cost[now];
if (tot < 0){
flag = false;
break;
}
}
if (flag) return (idx+1) % sz;
else return -1;
}
};