LeetCode 刷题【134. 加油站】

134. 加油站

自己做（超时）

class Solution {public int canCompleteCircuit(int[] gas, int[] cost) {int res = -1;for(int i = 0; i < gas.length; i++){int sum = 0;//顺时针走for(int j = 0; j < gas.length; j++){int index = (i + j) % gas.length;sum += gas[index] - cost[index];if(sum < 0){                             //走不到sum = 0;break;}if(j == gas.length - 1)                //走通了res = i;}if(res != -1)                               //如果已经走通就没必要再走了break;}return res;}
}

看题解

官方题解

class Solution {public int canCompleteCircuit(int[] gas, int[] cost) {int n = gas.length;int i = 0;while (i < n) {int sumOfGas = 0, sumOfCost = 0;int cnt = 0;while (cnt < n) {int j = (i + cnt) % n;sumOfGas += gas[j];sumOfCost += cost[j];if (sumOfCost > sumOfGas) {break;}cnt++;}if (cnt == n) {return i;} else {i = i + cnt + 1;}}return -1;}
}