LeetCode134☞加油站

关联LeetCode题号134

本题特点

• 贪心
• 局部最优解-部分差值 如果小于0（消耗大于油站油量） 就从下一个加油站开始，因为如果中间有小于0的情况 当前站就不可能是始发站，
• 整体最优解-整体差值 如果小于0 ，那么就是不能有始发站

本题思路

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

java写法

package leetcode;

import org.junit.jupiter.api.Test;

/**
 * File Description: gasStation_134
 * Author: Your Name
 * Date: 2024/12/24
 */
public class gasStation_134 {

    public int canCompleteCircuit(int[] gas, int[] cost) {
        int curSum = 0;
        int totalSum = 0;
        int start = 0;
        for (int i = 0; i < gas.length; i++){
            curSum += gas[i] - cost[i];
            totalSum += gas[i] - cost[i];
            if(curSum < 0){
                start = i + 1;
                curSum = 0;
            }
        }
        if (totalSum < 0){
            return -1;
        }
        return start;

    }

    @Test
    public void TestCanCompleteCircuit() {
        int[] gas = {2,3,4};
        int[] cost = {3,4,3};
        int start = canCompleteCircuit(gas, cost);
        System.out.println(start);
    }

}