Add solution and test-cases for problem 2220

Author: 0xff-dev

leetcode/2201-2300/2220.Minimum-Bit-Flips-to-Convert-Number/README.md

@@ -1,28 +1,35 @@
 # [2220.Minimum Bit Flips to Convert Number][title]
 
-> [!WARNING|style:flat]
-> This question is temporarily unanswered if you have good ideas. Welcome to [Create Pull Request PR](https://github.com/kylesliu/awesome-golang-algorithm)
-
 ## Description
+A **bit flip** of a number `x` is choosing a bit in the binary representation of `x` and **flipping** it from either `0` to `1` or `1` to `0`.
+
+- For example, for `x = 7`, the binary representation is `111` and we may choose any bit (including any leading zeros not shown) and flip it. We can flip the first bit from the right to get `110`, flip the second bit from the right to get `101`, flip the fifth bit from the right (a leading zero) to get `10111`, etc.
+
+Given two integers `start` and `goal`, return the **minimum** number of **bit flips** to convert `start` to `goal`.
 
 **Example 1:**
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: start = 10, goal = 7
+Output: 3
+Explanation: The binary representation of 10 and 7 are 1010 and 0111 respectively. We can convert 10 to 7 in 3 steps:
+- Flip the first bit from the right: 1010 -> 1011.
+- Flip the third bit from the right: 1011 -> 1111.
+- Flip the fourth bit from the right: 1111 -> 0111.
+It can be shown we cannot convert 10 to 7 in less than 3 steps. Hence, we return 3.
 ```
 
-## 题意
-> ...
+**Example 2:**
 
-## 题解
-
-### 思路1
-> ...
-Minimum Bit Flips to Convert Number
-```go
 ```
-
+Input: start = 3, goal = 4
+Output: 3
+Explanation: The binary representation of 3 and 4 are 011 and 100 respectively. We can convert 3 to 4 in 3 steps:
+- Flip the first bit from the right: 011 -> 010.
+- Flip the second bit from the right: 010 -> 000.
+- Flip the third bit from the right: 000 -> 100.
+It can be shown we cannot convert 3 to 4 in less than 3 steps. Hence, we return 3.
+```
 
 ## 结语
 

leetcode/2201-2300/2220.Minimum-Bit-Flips-to-Convert-Number/Solution.go

@@ -1,5 +1,11 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+func Solution(start int, goal int) int {
+	x := start ^ goal
+	n := 0
+	for x > 0 {
+		n++
+		x = x & (x - 1)
+	}
+	return n
 }

leetcode/2201-2300/2220.Minimum-Bit-Flips-to-Convert-Number/Solution_test.go

@@ -9,31 +9,30 @@ import (
 func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
-		name   string
-		inputs bool
-		expect bool
+		name        string
+		start, goal int
+		expect      int
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", 10, 7, 3},
+		{"TestCase2", 3, 4, 3},
 	}
 
 	//	开始测试
 	for i, c := range cases {
 		t.Run(c.name+" "+strconv.Itoa(i), func(t *testing.T) {
-			got := Solution(c.inputs)
+			got := Solution(c.start, c.goal)
 			if !reflect.DeepEqual(got, c.expect) {
-				t.Fatalf("expected: %v, but got: %v, with inputs: %v",
-					c.expect, got, c.inputs)
+				t.Fatalf("expected: %v, but got: %v, with inputs: %v %v",
+					c.expect, got, c.start, c.goal)
 			}
 		})
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }