860. 柠檬水找零

Author: w2xi

README.md

@@ -186,6 +186,7 @@
 |704|[二分查找](https://leetcode.cn/problems/binary-search/)|[JavaScript](./algorithms/binary-search.js)|Easy|
 |707|[设计链表](https://leetcode.cn/problems/design-linked-list/)|[JavaScript](./algorithms/design-linked-list.js)|Medium|
 |844|[比较含退格的字符串](https://leetcode.cn/problems/backspace-string-compare/)|[JavaScript](./algorithms/backspace-string-compare.js)|Easy|
+|860|[柠檬水找零](https://leetcode.cn/problems/lemonade-change/)|[JavaScript](./algorithms/lemonade-change.js)|Easy|
 |876|[链表的中间结点](https://leetcode.cn/problems/middle-of-the-linked-list/)|[JavaScript](./algorithms/middle-of-the-linked-list.js)|Easy|
 |897|[递增顺序搜索树](https://leetcode.cn/problems/increasing-order-search-tree/)|[JavaScript](./algorithms/increasing-order-search-tree.js)|Easy|
 |904|[水果成篮](https://leetcode.cn/problems/fruit-into-baskets/)|[JavaScript](./algorithms/fruit-into-baskets.js)|Medium|

algorithms/lemonade-change.js

@@ -0,0 +1,33 @@
+/**
+ * 860. 柠檬水找零
+ * @param {number[]} bills
+ * @return {boolean}
+ */
+var lemonadeChange = function (bills) {
+  // 面额: 5 10 20
+
+  let five = 0;
+  let ten = 0;
+
+  for (let i = 0; i < bills.length; i++) {
+    const curr = bills[i];
+    if (curr === 5) {
+      five++;
+    } else if (curr === 10) {
+      ten++;
+      five--; // 找零 5
+    } else if (ten > 0) {
+      // curr: 20, 找零 5, 10
+      ten--;
+      five--;
+    } else {
+      // curr: 20, 找零 5 * 3
+      five -= 3;
+    }
+    if (five < 0) {
+      return false;
+    }
+  }
+
+  return true;
+};