From 2877f751dce4dfdb7a325e5cc55811200ccaceb4 Mon Sep 17 00:00:00 2001
From: fancl <fancl@justcall.cn>
Date: Tue, 22 Aug 2023 16:11:34 +0800
Subject: [PATCH] fix bugs

---
 util/arrays/array.go      | 43 +++++++++++++++++++++++
 util/arrays/array_test.go | 73 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 116 insertions(+)
 create mode 100644 util/arrays/array.go
 create mode 100644 util/arrays/array_test.go

diff --git a/util/arrays/array.go b/util/arrays/array.go
new file mode 100644
index 0000000..c93313f
--- /dev/null
+++ b/util/arrays/array.go
@@ -0,0 +1,43 @@
+package arrays
+
+func IndexOf[T comparable](a T, vs []T) int {
+	for i, v := range vs {
+		if v == a {
+			return i
+		}
+	}
+	return -1
+}
+
+func Exists[T comparable](a T, vs []T) bool {
+	return IndexOf(a, vs) > -1
+}
+
+func Fill[T any](startIndex int, num uint, value T) map[int]T {
+	m := make(map[int]T)
+	var i uint
+	for i = 0; i < num; i++ {
+		m[startIndex] = value
+		startIndex++
+	}
+	return m
+}
+
+func Reverse[T comparable](s []T) []T {
+	for i, j := 0, len(s)-1; i < j; i, j = i+1, j-1 {
+		s[i], s[j] = s[j], s[i]
+	}
+	return s
+}
+
+func Merge[T comparable](ss ...[]T) []T {
+	n := 0
+	for _, v := range ss {
+		n += len(v)
+	}
+	s := make([]T, 0, n)
+	for _, v := range ss {
+		s = append(s, v...)
+	}
+	return s
+}
diff --git a/util/arrays/array_test.go b/util/arrays/array_test.go
new file mode 100644
index 0000000..ac2cc27
--- /dev/null
+++ b/util/arrays/array_test.go
@@ -0,0 +1,73 @@
+package arrays
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestIndexOf(t *testing.T) {
+	type args[T comparable] struct {
+		a  T
+		vs []T
+	}
+	type testCase[T comparable] struct {
+		name string
+		args args[T]
+		want int
+	}
+	tests := []testCase[string]{
+		{"exists", args[string]{a: "a", vs: []string{"a", "b"}}, 0},
+		{"not exists", args[string]{a: "a", vs: []string{"c", "b"}}, -1},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := IndexOf(tt.args.a, tt.args.vs); got != tt.want {
+				t.Errorf("IndexOf() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestExists(t *testing.T) {
+	type args[T comparable] struct {
+		a  T
+		vs []T
+	}
+	type testCase[T comparable] struct {
+		name string
+		args args[T]
+		want bool
+	}
+	tests := []testCase[int]{
+		{"exists", args[int]{a: 1, vs: []int{1, 2}}, true},
+		{"not exists", args[int]{a: 2, vs: []int{3, 4}}, false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := Exists(tt.args.a, tt.args.vs); got != tt.want {
+				t.Errorf("Exists() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestReverse(t *testing.T) {
+	type args[T comparable] struct {
+		s []T
+	}
+	type testCase[T comparable] struct {
+		name string
+		args args[T]
+		want []T
+	}
+	tests := []testCase[int]{
+		{"one", args[int]{s: []int{1, 2, 3}}, []int{3, 2, 1}},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := Reverse(tt.args.s); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("Reverse() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}