134. 加油站

原题

https://leetcode.cn/problems/gas-station/description/

思路

贪心

复杂度

时间：O(n)
空间：O(n)

Python代码

class Solution:
    def canCompleteCircuit(self, gas: List[int], cost: List[int]) -> int:
        ans = 0 
        cur_remain  = 0 
        total_remain = 0
        n = len(gas)
        for i in range(n):
            cur_remain += gas[i] - cost[i]
            total_remain += gas[i] - cost[i]
            if cur_remain < 0:
                ans = i + 1 
                cur_remain = 0 
        if total_remain < 0:
            return -1 
        return ans 
        

Go代码

func canCompleteCircuit(gas []int, cost []int) int {
	ans := 0
	cur_remain := 0
	total_remain := 0
	for i := 0; i < len(gas); i++ {
		cur_remain += gas[i] - cost[i]
		total_remain += gas[i] - cost[i]
        // 0-i之间无法绕环路行驶一周
		if cur_remain < 0 {
			ans = i + 1
			cur_remain = 0
		}
	}
    // 0-n之间无法绕环路行驶一周
	if total_remain < 0 {
		return -1
	} else {
		return ans
	}
}