feat(860): finish this

Author: plh97

README.md

@@ -8,16 +8,9 @@
 ## 刷题原则
 
 - 广度优先
-- 人的注意力只有半小时
+- 人的注意力只有半小时,所以
 - 测试覆盖率 100%
 
-## first
-
-- 不知道特定的算法,数据结构
-- 没有正确的思维方式
-- 不知道最优解在哪里想
-- 做题没有任何感觉,代码不知道从哪里写起
-
 ## vscode-debug-for-golang
 
 ```json

algorithm/860.LemonadeChange/README.md

@@ -0,0 +1,58 @@
+# [860. Lemonade Change](https://leetcode.com/problems/lemonade-change/)
+
+## 2019/06/05
+
+### 题目 💗[easy]
+
+At a lemonade stand, each lemonade costs `$5`.
+
+Customers are standing in a queue to buy from you, and order one at a time (in the order specified by `bills`).
+
+Each customer will only buy one lemonade and pay with either a `$5`, `$10`, or `$20` bill.  You must provide the correct change to each customer, so that the net transaction is that the customer pays `$5`.
+
+Note that you don't have any change in hand at first.
+
+Return true if and only if you can provide every customer with correct change.
+
+Example 1:
+
+```bash
+Input: [5,5,5,10,20]
+Output: true
+Explanation:
+From the first 3 customers, we collect three $5 bills in order.
+From the fourth customer, we collect a $10 bill and give back a $5.
+From the fifth customer, we give a $10 bill and a $5 bill.
+Since all customers got correct change, we output true.
+```
+
+Example 2:
+
+```bash
+Input: [5,5,10]
+Output: true
+```
+
+Example 3:
+
+```bash
+Input: [10,10]
+Output: false
+```
+
+Example 4:
+
+```bash
+Input: [5,5,10,10,20]
+Output: false
+Explanation:
+From the first two customers in order, we collect two $5 bills.
+For the next two customers in order, we collect a $10 bill and give back a $5 bill.
+For the last customer, we can't give change of $15 back because we only have two $10 bills.
+Since not every customer received correct change, the answer is false.
+```
+
+Note:
+
+1. 0 <= bills.length <= 10000
+2. bills[i] will be either 5, 10, or 20.

algorithm/860.LemonadeChange/main.go

@@ -0,0 +1,30 @@
+package lemonadeChange
+
+func lemonadeChange(bills []int) bool {
+	five := 0
+	ten := 0
+	for _, e := range bills {
+		switch e {
+		case 5:
+			five++
+		case 10:
+			if five > 0 {
+				// 付得起
+				five--
+				ten++
+			} else {
+				return false
+			}
+		case 20:
+			if ten > 0 && five > 0 {
+				ten--
+				five--
+			} else if five > 2 {
+				five -= 3
+			} else {
+				return false
+			}
+		}
+	}
+	return true
+}

algorithm/860.LemonadeChange/main_test.go

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+package lemonadeChange
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+var tcs = []struct {
+	N1  []int
+	ans bool
+}{
+	{
+		[]int{5, 5, 5, 10, 20},
+		true,
+	},
+	{
+		[]int{5, 5, 10},
+		true,
+	},
+	{
+		[]int{10, 10},
+		false,
+	},
+	{
+		[]int{5, 5, 10, 10, 20},
+		false,
+	},
+	{
+		[]int{5, 5, 5, 5, 20, 20, 5, 5, 20, 5},
+		false,
+	},
+	{
+		[]int{5, 5, 10, 20, 5, 5, 5, 5, 5, 5, 5, 5, 5, 10, 5, 5, 20, 5, 20, 5},
+		true,
+	},
+	{
+		[]int{5, 5, 5, 20, 5, 5, 5, 20, 5, 5, 5, 10, 5, 20, 10, 20, 10, 20, 5, 5},
+		false,
+	},
+}
+
+func Test_bitwiseComplement(t *testing.T) {
+	ast := assert.New(t)
+	for _, tc := range tcs {
+		ast.Equal(tc.ans, lemonadeChange(tc.N1), "输入:%v", tc)
+	}
+}