Merge pull request #731 from martisss/master

增加134.加油站 js解法

problems/0134.加油站.md

@@ -281,6 +281,48 @@ func canCompleteCircuit(gas []int, cost []int) int {
 ```
 
 Javascript:
+暴力：
+```js
+var canCompleteCircuit = function(gas, cost) {
+    for(let i = 0; i < cost.length; i++) {
+        let rest = gas[i] - cost[i]  //记录剩余油量
+        // 以i为起点行驶一圈，index为下一个目的地
+        let index = (i + 1) % cost.length
+        while(rest > 0 && index !== i) {
+            rest += gas[index] - cost[index]
+            index = (index + 1) % cost.length
+        }
+        if(rest >= 0 && index === i) return i
+    }
+    return -1
+};
+```
+解法一：
+```js
+var canCompleteCircuit = function(gas, cost) {
+    let curSum = 0
+    let min = Infinity
+    for(let i = 0; i < gas.length; i++) {
+        let rest = gas[i] - cost[i]
+        curSum += rest
+        if(curSum < min) {
+            min = curSum
+        }
+    }
+    if(curSum < 0) return -1   //1.总油量 小于 总消耗量
+    if(min >= 0) return 0      //2. 说明油箱里油没断过
+                               //3. 从后向前，看哪个节点能这个负数填平，能把这个负数填平的节点就是出发节点
+    for(let i = gas.length -1; i >= 0; i--) {
+        let rest = gas[i] - cost[i]
+        min += rest
+        if(min >= 0) {
+            return i
+        }
+    }
+    return -1
+}
+```
+解法二：
 ```Javascript
 var canCompleteCircuit = function(gas, cost) {
     const gasLen = gas.length