feat: 0070.Climbing Stairs

Author: kimi0230

Leetcode/0070.Climbing-Stairs/README.md

@@ -93,7 +93,7 @@ Constraints:
 * Acceptance Rate: 52.3%
 
 ## 題目大意
-
+類似 [Fibonacci Number](../0509.Fibonacci-Number/README.md)
 
 ## 解題思路
 
@@ -114,10 +114,57 @@ https://github.com/kimi0230/LeetcodeGolang/blob/master/Leetcode/0070.Climbing-St
 
 ```go
 
+package climbingstairs
+
+// 時間複雜 O(n), 空間複雜 O(n)
+func ClimbStairs(n int) int {
+	dp := make([]int, n+1)
+	dp[0], dp[1] = 1, 1
+
+	for i := 2; i <= n; i++ {
+		dp[i] = dp[i-1] + dp[i-2]
+	}
+	return dp[n]
+}
+
+func ClimbStairsCache(n int) int {
+	dp := make([]int, n+1)
+	dp[0], dp[1] = 1, 1
+
+	for i := 2; i <= n; i++ {
+		if val := dp[i]; val == 0 {
+			dp[i] = dp[i-1] + dp[i-2]
+		}
+	}
+	return dp[n]
+}
+
+func ClimbStairsRecursive(n int) int {
+	dp := make([]int, n+1)
+	// dp[0], dp[1] = 1, 1
+
+	var climbClosure func(n int) int
+	climbClosure = func(n int) int {
+		if n <= 2 {
+			return n
+		}
+		dp[n] = climbClosure(n-1) + climbClosure(n-2)
+		return dp[n]
+	}
+	return climbClosure(n)
+}
 ```
 
 ##  Benchmark
 
 ```sh
-
+goos: darwin
+goarch: amd64
+pkg: LeetcodeGolang/Leetcode/0070.Climbing-Stairs
+cpu: Intel(R) Core(TM) i5-8259U CPU @ 2.30GHz
+BenchmarkClimbStairs-8                  10386211               112.1 ns/op           320 B/op          1 allocs/op
+BenchmarkClimbStairsCache-8             10184984               118.8 ns/op           320 B/op          1 allocs/op
+BenchmarkClimbStairsRecursive-8                4         281980486 ns/op             320 B/op          1 allocs/op
+PASS
+ok      LeetcodeGolang/Leetcode/0070.Climbing-Stairs    5.591s
 ```

Leetcode/0070.Climbing-Stairs/main.go

@@ -11,6 +11,18 @@ func ClimbStairs(n int) int {
 	return dp[n]
 }
 
+func ClimbStairsCache(n int) int {
+	dp := make([]int, n+1)
+	dp[0], dp[1] = 1, 1
+
+	for i := 2; i <= n; i++ {
+		if val := dp[i]; val == 0 {
+			dp[i] = dp[i-1] + dp[i-2]
+		}
+	}
+	return dp[n]
+}
+
 func ClimbStairsRecursive(n int) int {
 	dp := make([]int, n+1)
 	// dp[0], dp[1] = 1, 1

Leetcode/0070.Climbing-Stairs/main_test.go

@@ -14,6 +14,10 @@ var tests = []struct {
 		3,
 		3,
 	},
+	{
+		39,
+		63245986,
+	},
 }
 
 func TestClimbStairs(t *testing.T) {
@@ -25,6 +29,15 @@ func TestClimbStairs(t *testing.T) {
 	}
 }
 
+func TestClimbStairsCache(t *testing.T) {
+	for _, tt := range tests {
+		// if got := ReverseList(tt.arg1); !reflect.DeepEqual(got, tt.want) {
+		if got := ClimbStairsCache(tt.arg1); got != tt.want {
+			t.Errorf("got = %v, want = %v", got, tt.want)
+		}
+	}
+}
+
 func TestClimbStairsRecursive(t *testing.T) {
 	for _, tt := range tests {
 		// if got := ReverseList(tt.arg1); !reflect.DeepEqual(got, tt.want) {
@@ -37,14 +50,21 @@ func TestClimbStairsRecursive(t *testing.T) {
 func BenchmarkClimbStairs(b *testing.B) {
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		ClimbStairs(tests[0].arg1)
+		ClimbStairs(tests[2].arg1)
+	}
+}
+
+func BenchmarkClimbStairsCache(b *testing.B) {
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		ClimbStairsCache(tests[2].arg1)
 	}
 }
 
 func BenchmarkClimbStairsRecursive(b *testing.B) {
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		ClimbStairsRecursive(tests[0].arg1)
+		ClimbStairsRecursive(tests[2].arg1)
 	}
 }
 
@@ -54,8 +74,9 @@ goos: darwin
 goarch: amd64
 pkg: LeetcodeGolang/Leetcode/0070.Climbing-Stairs
 cpu: Intel(R) Core(TM) i5-8259U CPU @ 2.30GHz
-BenchmarkClimbStairs-8                  40758399                30.75 ns/op           24 B/op          1 allocs/op
-BenchmarkClimbStairsRecursive-8         42196260                27.60 ns/op           24 B/op          1 allocs/op
+BenchmarkClimbStairs-8                  10386211               112.1 ns/op           320 B/op          1 allocs/op
+BenchmarkClimbStairsCache-8             10184984               118.8 ns/op           320 B/op          1 allocs/op
+BenchmarkClimbStairsRecursive-8                4         281980486 ns/op             320 B/op          1 allocs/op
 PASS
-ok      LeetcodeGolang/Leetcode/0070.Climbing-Stairs    2.489s
+ok      LeetcodeGolang/Leetcode/0070.Climbing-Stairs    5.591s
 */