ADD: math.A && math.C

app.go

@@ -1,6 +1,6 @@
 /*
  * @Author: NorthCity1984
- * @LastEditTime: 2022-04-26 17:05:06
+ * @LastEditTime: 2022-05-03 18:51:46
  * @Description:
  * @Website: https://grimoire.cn
  * Copyright (c) NorthCity1984 All rights reserved.
@@ -10,18 +10,18 @@ package main
 import (
 	"fmt"
 
-	"gitee.com/NorthCityChen/stl-go/bit"
+	"gitee.com/NorthCityChen/stl-go/math"
 )
 
 var a = []int{1, 2, 65, 4, 33, 5}
 
 func main() {
-	ans := a[0]
-	for i := len(a) - 1; i >= 1; i-- {
-		a[i] = a[i] - a[i-1]
-	}
-	b := bit.Init(a)
-	fmt.Println(b)
-	ans = b.Ask(6)
+	// h := heap.Init(a, heap.MinHeap[int]())
+	// fmt.Println(h)
+
+	ans := math.C(8, 2)
+	fmt.Println(ans)
+
+	ans = math.A(12, 2)
 	fmt.Println(ans)
 }

dequeue/dequeue.go

@@ -1,6 +1,6 @@
 /*
  * @Author: NorthCity1984
- * @LastEditTime: 2022-04-17 12:04:32
+ * @LastEditTime: 2022-04-27 13:31:14
  * @Description:
  * @Website: https://grimoire.cn
  * Copyright (c) NorthCity1984 All rights reserved.
@@ -24,6 +24,9 @@ type dequeueNode[T Number] struct {
 	RPointer *dequeueNode[T]
 }
 
+// 返回对应类型的零值 对比 T(Rune(0))在获取空字符串的情况下快14倍左右
+func zeroValue[T Number]() (value T) { return }
+
 func Init[T Number]() *Dequeue[T] {
 	return &Dequeue[T]{size: 0, leftHead: new(dequeueNode[T]), rightHead: new(dequeueNode[T])}
 }
@@ -50,7 +53,7 @@ func (q *Dequeue[T]) LPush(val T) bool {
 
 func (q *Dequeue[T]) LPop() (T, bool) {
 	if q.IsEmpty() {
-		return T(rune(0)), false
+		return zeroValue[T](), false
 	}
 	val := q.leftHead.Val
 	q.leftHead = q.leftHead.RPointer
@@ -72,7 +75,7 @@ func (q *Dequeue[T]) RPush(val T) bool {
 
 func (q *Dequeue[T]) RPop() (T, bool) {
 	if q.IsEmpty() {
-		return T(rune(0)), false
+		return zeroValue[T](), false
 	}
 	val := q.rightHead.Val
 	q.rightHead = q.rightHead.LPointer
@@ -82,14 +85,14 @@ func (q *Dequeue[T]) RPop() (T, bool) {
 
 func (q *Dequeue[T]) LNode() (T, bool) {
 	if q.IsEmpty() {
-		return T(rune(0)), false
+		return zeroValue[T](), false
 	}
 	return q.leftHead.Val, true
 }
 
 func (q *Dequeue[T]) RNode() (T, bool) {
 	if q.IsEmpty() {
-		return T(rune(0)), false
+		return zeroValue[T](), false
 	}
 	return q.rightHead.Val, true
 }

dequeue/dequeue_test.go

@@ -0,0 +1,50 @@
+/*
+ * @Author: NorthCity1984
+ * @LastEditTime: 2022-04-27 13:36:25
+ * @Description:
+ * @Website: https://grimoire.cn
+ * Copyright (c) NorthCity1984 All rights reserved.
+ */
+package dequeue
+
+import (
+	"testing"
+	// "gitee.com/NorthCityChen/stl-go/dequeue"
+)
+
+// type Number interface {
+// 	int | int64 | float32 | float64 | string
+// }
+
+// func zeroValue[T Number]() (value T) { return }
+func TRune[T Number]() T { return T(rune(0)) }
+
+func BenchmarkZeroValue(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		zeroValue[float64]()
+		zeroValue[float32]()
+		zeroValue[int]()
+		zeroValue[int64]()
+		zeroValue[string]()
+	}
+}
+
+func BenchmarkTRune(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		TRune[float64]()
+		TRune[float32]()
+		TRune[int64]()
+		TRune[int]()
+		TRune[string]()
+	}
+}
+
+func BenchmarkRunDequeue(b *testing.B) {
+	dq := Init[int]()
+	for i := 0; i < b.N; i++ {
+		dq.LPush(1)
+		dq.RPush(2)
+		dq.LPop()
+		dq.RPop()
+	}
+}

heap/heap.go

@@ -1,6 +1,6 @@
 /*
  * @Author: NorthCity1984
- * @LastEditTime: 2022-04-26 16:06:24
+ * @LastEditTime: 2022-04-27 13:19:36
  * @Description:
  * @Website: https://grimoire.cn
  * Copyright (c) NorthCity1984 All rights reserved.
@@ -17,6 +17,9 @@ type heap[T Number] struct {
 	cmp   func(T, T) bool
 }
 
+// 返回对应类型的零值
+func zeroValue[T Number]() (value T) { return }
+
 func (h *heap[T]) up(x int) {
 	for x > 1 && h.cmp(h.array[x], h.array[x/2]) {
 		h.array[x], h.array[x/2] = h.array[x/2], h.array[x]
@@ -46,7 +49,7 @@ func (h *heap[T]) Push(v T) {
 
 func (h *heap[T]) Pop() T {
 	if h.len == 0 {
-		return 0
+		return zeroValue[T]()
 	}
 	ret := h.array[1]
 	h.array[1], h.array[h.len] = h.array[h.len], h.array[1]
@@ -61,8 +64,10 @@ func (h *heap[T]) Top() T {
 }
 
 func Init[T Number](array []T, cmp func(T, T) bool) heap[T] {
+	newArray := make([]T, len(array)+1)
+	copy(newArray[1:], array)
 	h := heap[T]{
-		array: append([]T{0}, array...),
+		array: newArray,
 		len:   len(array),
 		cmp:   cmp,
 	}
@@ -71,3 +76,15 @@ func Init[T Number](array []T, cmp func(T, T) bool) heap[T] {
 	}
 	return h
 }
+
+func MaxHeap[T Number]() func(T, T) bool {
+	return func(t1, t2 T) bool {
+		return t1 > t2
+	}
+}
+
+func MinHeap[T Number]() func(T, T) bool {
+	return func(t1, t2 T) bool {
+		return t1 < t2
+	}
+}

math/math.go

@@ -1,6 +1,6 @@
 /*
  * @Author: NorthCity1984
- * @LastEditTime: 2022-04-03 09:32:48
+ * @LastEditTime: 2022-05-03 18:50:22
  * @Description:
  * @Website: https://grimoire.cn
  * Copyright (c) NorthCity1984 All rights reserved.
@@ -77,3 +77,21 @@ func Sqrt(x float64) float64 {
 	}
 	return res
 }
+
+// 排列数： A(3,1)=3
+func A(n, m int) int {
+	res := 1
+	for i := m; i >= 1; i-- {
+		res *= n //n × n-1 × n-2 × ... n-m，m就是需要减1的次数
+		n--
+	}
+	return res
+}
+
+// 组合数：C(3, 2)=3
+func C(n, m int) int {
+	if m == 0 {
+		return 1
+	}
+	return C(n-1, m-1) * (n / m)
+}