650 finish

Author: aQua

Algorithms/0650.2-keys-keyboard/2-keys-keyboard.go

@@ -0,0 +1,15 @@
+package Problem0650
+
+func minSteps(n int) int {
+	if n == 1 {
+		return 0
+	}
+
+	for i := 2; i < n; i++ {
+		if n%i == 0 {
+			return i + minSteps(n/i)
+		}
+	}
+
+	return n
+}

Algorithms/0650.2-keys-keyboard/2-keys-keyboard_test.go

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+package Problem0650
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// tcs is testcase slice
+var tcs = []struct {
+	n   int
+	ans int
+}{
+
+	{
+		100,
+		14,
+	},
+
+	{
+		1,
+		0,
+	},
+
+	{
+		3,
+		3,
+	},
+
+	// 可以有多个 testcase
+}
+
+func Test_fn(t *testing.T) {
+	ast := assert.New(t)
+
+	for _, tc := range tcs {
+		fmt.Printf("~~%v~~\n", tc)
+		ast.Equal(tc.ans, minSteps(tc.n), "输入:%v", tc)
+	}
+}
+
+func Benchmark_fn(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		for _, tc := range tcs {
+			minSteps(tc.n)
+		}
+	}
+}

Algorithms/0650.2-keys-keyboard/README.md

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+# [650. 2 Keys Keyboard](https://leetcode.com/problems/2-keys-keyboard/)
+
+## 题目
+
+Initially on a notepad only one character 'A' is present. You can perform two operations on this notepad for each step:
+
+Copy All: You can copy all the characters present on the notepad (partial copy is not allowed).
+
+Paste: You can paste the characters which are copied last time.
+
+Given a number n. You have to get exactly n 'A' on the notepad by performing the minimum number of steps permitted. Output the minimum number of steps to get n 'A'.
+
+Example 1:
+
+```text
+Input: 3
+Output: 3
+Explanation:
+Intitally, we have one character 'A'.
+In step 1, we use Copy All operation.
+In step 2, we use Paste operation to get 'AA'.
+In step 3, we use Paste operation to get 'AAA'.
+```
+
+Note:
+The n will be in the range [1, 1000].
+
+
+## 解题思路
+
+见程序注释