Add Map/Reduce Methods

algorithm/helper.go

@@ -73,6 +73,21 @@ func UniqueBy[T any, K cmp.Ordered, A ~[]T](arr A, getKey func(item T) K) A {
 	return arr
 }
 
+// Sum 求和
+func Sum[T cmp.Number](arr []T) T {
+	var sum T
+	return Reduce(arr, sum, func(s T, item T) T { return s + item })
+}
+
+// Reduce 对数组中的每个元素按序执行一个提供的 reducer 函数，每一次运行 reducer 会将先前元素的计算结果作为参数传入，
+// 最后将其结果汇总为单个返回值。
+func Reduce[T any, S any](arr []T, initialValue S, reducer func(s S, item T) S) S {
+	for _, item := range arr {
+		initialValue = reducer(initialValue, item)
+	}
+	return initialValue
+}
+
 // Reverse 反转数组
 func Reverse[T any, A ~[]T](arr A) A {
 	var n = len(arr)

algorithm/helper_test.go

@@ -1,6 +1,7 @@
 package algorithm
 
 import (
+	"github.com/lxzan/dao/hashmap"
 	"github.com/lxzan/dao/internal/utils"
 	"github.com/stretchr/testify/assert"
 	"math/rand"
@@ -182,3 +183,29 @@ func TestIsZero(t *testing.T) {
 	assert.False(t, IsZero(1))
 	assert.False(t, IsZero(" "))
 }
+
+func TestReduce(t *testing.T) {
+	t.Run("", func(t *testing.T) {
+		var arr = []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
+		var sum = Reduce(arr, 0, func(summarize int, item int) int {
+			return summarize + item
+		})
+		assert.Equal(t, sum, 55)
+	})
+
+	t.Run("", func(t *testing.T) {
+		var arr = []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
+		var m = hashmap.New[int, struct{}](10)
+		Reduce(arr, m, func(s hashmap.HashMap[int, struct{}], item int) hashmap.HashMap[int, struct{}] {
+			s.Set(item, struct{}{})
+			return s
+		})
+		assert.ElementsMatch(t, m.Keys(), []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10})
+	})
+}
+
+func TestSum(t *testing.T) {
+	assert.Equal(t, Sum([]int{}), 0)
+	assert.Equal(t, Sum([]int{1, 3, 5, 7, 9}), 25)
+	assert.Equal(t, Sum([]uint32{1, 3, 5, 7, 9}), uint32(25))
+}

heap/heap_test.go

@@ -2,16 +2,72 @@ package heap
 
 import (
 	"fmt"
+	"github.com/lxzan/dao/algorithm"
 	"github.com/lxzan/dao/internal/utils"
 	"github.com/lxzan/dao/types/cmp"
 	"github.com/stretchr/testify/assert"
+	"math/rand"
 	"sort"
 	"testing"
 	"unsafe"
 )
 
-func desc[T cmp.Ordered](a, b T) bool {
-	return a > b
+func compareDesc[T cmp.Ordered](x, y T) int { return -1 * cmp.Compare(x, y) }
+
+func validateHeap[T cmp.Ordered](t *testing.T, h *Heap[T], compare cmp.CompareFunc[T]) {
+	var n = h.Len()
+	if n > 0 {
+		assert.Equal(t, h.data[0], h.Top())
+	}
+
+	var i = 0
+	h.Range(func(index int, value T) bool {
+		i++
+
+		var base = index << h.bits
+		var end = algorithm.Min(base+h.ways, n-1)
+		for j := base + 1; j <= end; j++ {
+			child := h.data[j]
+			assert.True(t, compare(value, child) <= 0)
+		}
+		return true
+	})
+
+	var keys = make([]T, 0, n)
+	for h.Len() > 0 {
+		keys = append(keys, h.Pop())
+	}
+	assert.True(t, algorithm.IsSorted(keys, compare))
+}
+
+func TestHeap_Random(t *testing.T) {
+	const count = 10000
+
+	var f = func(ways uint32, lessFunc cmp.LessFunc[int], compareFunc cmp.CompareFunc[int]) {
+		var h = NewWithWays[int](ways, lessFunc)
+		h.SetCap(count)
+		for i := 0; i < count; i++ {
+			flag := rand.Intn(3)
+			key := rand.Intn(count)
+			switch flag {
+			case 0, 1:
+				h.Push(key)
+			case 2:
+				h.Pop()
+			}
+		}
+
+		validateHeap(t, h, compareFunc)
+	}
+
+	f(2, cmp.Less[int], cmp.Compare[int])
+	f(2, cmp.Great[int], compareDesc[int])
+	f(4, cmp.Less[int], cmp.Compare[int])
+	f(4, cmp.Great[int], compareDesc[int])
+	f(8, cmp.Less[int], cmp.Compare[int])
+	f(8, cmp.Great[int], compareDesc[int])
+	f(16, cmp.Less[int], cmp.Compare[int])
+	f(16, cmp.Great[int], compareDesc[int])
 }
 
 func TestNew(t *testing.T) {
@@ -36,7 +92,7 @@ func TestNew(t *testing.T) {
 }
 
 func TestDesc(t *testing.T) {
-	var h = NewWithWays(Octal, desc[int])
+	var h = NewWithWays(Octal, cmp.Great[int])
 	h.SetCap(8)
 	h.Push(1)
 	assert.Equal(t, h.Top(), 1)

heap/index_test.go

@@ -11,90 +11,54 @@ import (
 	"unsafe"
 )
 
-func TestIndexedHeap_Sort(t *testing.T) {
-	var h = NewIndexedHeap[int, struct{}](Quadratic, nil)
-	for i := 0; i < 1000; i++ {
-		h.Push(rand.Int(), struct{}{})
-	}
-	var arr []int
-	for h.Len() > 0 {
-		arr = append(arr, h.Pop().Key())
+func validateIndexedHeap[K cmp.Ordered, V any](t *testing.T, h *IndexedHeap[K, V], compare cmp.CompareFunc[K]) {
+	var n = h.Len()
+	if n > 0 {
+		assert.Equal(t, h.data[0].Key(), h.Top().Key())
 	}
-	assert.True(t, algorithm.IsSorted(arr, func(a, b int) int {
-		if a > b {
-			return 1
-		} else if a < b {
-			return -1
-		} else {
-			return 0
-		}
-	}))
-}
-
-func TestHeap_Random(t *testing.T) {
-	t.Run("asc", func(t *testing.T) {
-		const count = 10000
-		var h = NewIndexedHeap[int, struct{}](Quadratic, cmp.Less[int])
-		h.SetCap(count)
-		for i := 0; i < count; i++ {
-			flag := rand.Intn(5)
-			key := rand.Intn(count)
-			switch flag {
-			case 0, 1:
-				h.Push(key, struct{}{})
-			case 2:
-				h.Pop()
-			case 3:
-				n := h.Len()
-				if n > 0 {
-					index := rand.Intn(n)
-					h.UpdateKeyByIndex(index, key)
-				}
-			case 4:
-				n := h.Len()
-				if n > 0 {
-					index := rand.Intn(n)
-					h.DeleteByIndex(index)
-				}
-			}
-		}
 
-		for i, item := range h.data {
-			assert.Equal(t, item.Index(), i)
+	var i = 0
+	h.Range(func(ele *Element[K, V]) bool {
+		assert.Equal(t, ele.Index(), i)
+		i++
 
-			if item.Index() == 0 {
-				item = h.Top()
-			}
-			var n = h.Len()
-			var base = i << h.bits
-			var end = algorithm.Min(base+h.ways, n-1)
-			for j := base + 1; j <= end; j++ {
-				assert.True(t, h.lessFunc(item.Key(), h.GetByIndex(j).Key()))
-			}
+		var base = ele.Index() << h.bits
+		var end = algorithm.Min(base+h.ways, n-1)
+		for j := base + 1; j <= end; j++ {
+			child := h.GetByIndex(j)
+			assert.True(t, compare(ele.Key(), child.Key()) <= 0)
 		}
+		return true
 	})
 
-	t.Run("desc", func(t *testing.T) {
-		const count = 10000
-		var h = NewIndexedHeap[int, struct{}](Quadratic, func(a, b int) bool {
-			return a > b
-		})
+	var keys = make([]K, 0, n)
+	for h.Len() > 0 {
+		keys = append(keys, h.Pop().Key())
+	}
+	assert.True(t, algorithm.IsSorted(keys, compare))
+}
+
+func TestIndexedHeap_Random(t *testing.T) {
+	const count = 10000
+
+	var f = func(ways uint32, lessFunc cmp.LessFunc[int], compareFunc cmp.CompareFunc[int]) {
+		var h = NewIndexedHeap[int, struct{}](ways, lessFunc)
 		h.SetCap(count)
 		for i := 0; i < count; i++ {
-			flag := rand.Intn(5)
+			flag := utils.Alphabet.Intn(6)
 			key := rand.Intn(count)
 			switch flag {
-			case 0, 1:
+			case 0, 1, 2:
 				h.Push(key, struct{}{})
-			case 2:
-				h.Pop()
 			case 3:
+				h.Pop()
+			case 4:
 				n := h.Len()
 				if n > 0 {
 					index := rand.Intn(n)
 					h.UpdateKeyByIndex(index, key)
 				}
-			case 4:
+			case 5:
 				n := h.Len()
 				if n > 0 {
 					index := rand.Intn(n)
@@ -103,20 +67,37 @@ func TestHeap_Random(t *testing.T) {
 			}
 		}
 
-		for i, item := range h.data {
-			assert.Equal(t, item.Index(), i)
+		validateIndexedHeap(t, h, compareFunc)
+	}
 
-			if item.Index() == 0 {
-				item = h.Top()
-			}
-			var n = h.Len()
-			var base = i << h.bits
-			var end = algorithm.Min(base+h.ways, n-1)
-			for j := base + 1; j <= end; j++ {
-				assert.True(t, h.lessFunc(item.Key(), h.GetByIndex(j).Key()))
-			}
+	f(2, cmp.Less[int], cmp.Compare[int])
+	f(2, cmp.Great[int], compareDesc[int])
+	f(4, cmp.Less[int], cmp.Compare[int])
+	f(4, cmp.Great[int], compareDesc[int])
+	f(8, cmp.Less[int], cmp.Compare[int])
+	f(8, cmp.Great[int], compareDesc[int])
+	f(16, cmp.Less[int], cmp.Compare[int])
+	f(16, cmp.Great[int], compareDesc[int])
+}
+
+func TestIndexedHeap_Sort(t *testing.T) {
+	var h = NewIndexedHeap[int, struct{}](Quadratic, nil)
+	for i := 0; i < 1000; i++ {
+		h.Push(rand.Int(), struct{}{})
+	}
+	var arr []int
+	for h.Len() > 0 {
+		arr = append(arr, h.Pop().Key())
+	}
+	assert.True(t, algorithm.IsSorted(arr, func(a, b int) int {
+		if a > b {
+			return 1
+		} else if a < b {
+			return -1
+		} else {
+			return 0
 		}
-	})
+	}))
 }
 
 func TestIndexedHeap_Range(t *testing.T) {

internal/utils/helper.go

@@ -37,6 +37,13 @@ func (c *RandomString) Generate(n int) string {
 	return string(b)
 }
 
+func (c *RandomString) Intn(n int) int {
+	c.mu.Lock()
+	v := c.rand.Intn(n)
+	c.mu.Unlock()
+	return v
+}
+
 func IsSameSlice[T comparable](a, b []T) bool {
 	if len(a) != len(b) {
 		return false

internal/utils/helper_test.go

@@ -27,6 +27,12 @@ func TestRandomString_Generate(t *testing.T) {
 	assert.Equal(t, len(s), 6)
 }
 
+func TestRandomString_Intn(t *testing.T) {
+	for i := 0; i < 100; i++ {
+		v := Alphabet.Intn(i + 10)
+		assert.True(t, v < i+10)
+	}
+}
 func TestReverseStrings(t *testing.T) {
 	{
 		var arr = []string{"a", "b", "c"}

types/cmp/cmp.go

@@ -32,9 +32,12 @@ type (
 	CompareFunc[T any] func(a, b T) int
 )
 
-// Less 比大小函数(升序)
+// Less 小于
 func Less[T Ordered](x, y T) bool { return x < y }
 
+// Great 大于
+func Great[T Ordered](x, y T) bool { return x > y }
+
 // Compare 比较函数(升序)
 func Compare[T Ordered](x, y T) int {
 	if x < y {