feat: 回溯 2021年05月26日23:41:38

Author: chen-shiwei

leetcode/0078_todo/subsets.go

@@ -0,0 +1,31 @@
+package _8_子集
+
+func subsets(nums []int) [][]int {
+	var (
+		path  []int
+		paths [][]int
+		fn    func(nums []int, startIdx int)
+	)
+
+	fn = func(nums []int, startIdx int) {
+		tmp := make([]int, len(path))
+		copy(tmp, path)
+		paths = append(paths, tmp)
+		if startIdx >= len(nums) {
+			//tmp := make([]int, len(path))
+			//copy(tmp, path)
+			//paths = append(paths, tmp)
+			return
+		}
+
+		for i := startIdx; i < len(nums); i++ {
+			path = append(path, nums[i])
+			fn(nums, i+1)
+			path = path[:len(path)-1]
+		}
+	}
+
+	fn(nums, 0)
+
+	return paths
+}

leetcode/78.子集/subsets.go

@@ -1,4 +1,4 @@
-package _078_todo
+package _8_子集
 
 import (
 	"reflect"
@@ -33,7 +33,7 @@ func TestSubsets(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			if got := Subsets(tt.args.nums); !reflect.DeepEqual(got, tt.want) {
+			if got := subsets(tt.args.nums); !reflect.DeepEqual(got, tt.want) {
 				t.Errorf("Subsets() = %v, want %v", got, tt.want)
 			}
 		})

leetcode/0078_todo/subsets_test.go renamed to leetcode/78.子集/subsets_test.go

@@ -0,0 +1,40 @@
+package _0_子集II
+
+import "sort"
+
+func subsetsWithDup(nums []int) [][]int {
+	var (
+		used  = make([]bool, len(nums))
+		path  []int
+		paths [][]int
+		fn    func(nums []int, startIdx int)
+	)
+
+	fn = func(nums []int, startIdx int) {
+		tmp := make([]int, len(path))
+		copy(tmp, path)
+		paths = append(paths, tmp)
+		if startIdx >= len(nums) {
+			//tmp := make([]int, len(path))
+			//copy(tmp, path)
+			//paths = append(paths, tmp)
+			return
+		}
+
+		for i := startIdx; i < len(nums); i++ {
+			if i > 0 && nums[i] == nums[i-1] && !used[i-1] {
+				continue
+			}
+			path = append(path, nums[i])
+			used[i] = true
+			fn(nums, i+1)
+			used[i] = false
+			path = path[:len(path)-1]
+		}
+	}
+	sort.Ints(nums)
+
+	fn(nums, 0)
+
+	return paths
+}

leetcode/90.子集II/subsetsWithDup.go

@@ -0,0 +1,29 @@
+package _0_子集II
+
+import (
+	"reflect"
+	"testing"
+)
+
+func Test_subsetsWithDup(t *testing.T) {
+	type args struct {
+		nums []int
+	}
+	tests := []struct {
+		name string
+		args args
+		want [][]int
+	}{
+		{name: `输入：nums = [1,2,2]
+输出：[[],[1],[1,2],[1,2,2],[2],[2,2]]`, args: args{nums: []int{1, 2, 2}}, want: [][]int{
+			{}, {1}, {1, 2}, {1, 2, 2}, {2}, {2, 2},
+		}},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := subsetsWithDup(tt.args.nums); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("subsetsWithDup() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

leetcode/90.子集II/subsetsWithDup_test.go

@@ -1,7 +1,5 @@
 package _3_复原IP地址
 
-import "fmt"
-
 func restoreIpAddresses(s string) []string {
 	var (
 		paths []string
@@ -10,24 +8,21 @@ func restoreIpAddresses(s string) []string {
 
 	fn = func(s string, startIdx int, n int) {
 		if n == 3 {
-			fmt.Println("==3", n, s, s[startIdx:], isValidIP(s, startIdx, len(s)-1))
 			if isValidIP(s, startIdx, len(s)-1) {
-				fmt.Println("append", s)
 				paths = append(paths, s)
 			}
 			return
 		}
 
 		for i := startIdx; i < len(s); i++ {
-			fmt.Println("isValidIP", string(s[startIdx:i+1]), isValidIP(s, startIdx, i))
 			if !isValidIP(s, startIdx, i) {
 				continue
 			}
-			s = s[:startIdx+i+1] + "." + s[startIdx+i+1:]
+			s = s[:i+1] + "." + s[i+1:]
 			n++
 			fn(s, i+2, n)
 			n--
-			s = s[:startIdx+i+1] + s[startIdx+i+2:]
+			s = s[:i+1] + s[i+2:]
 		}
 	}
 	fn(s, 0, 0)
@@ -36,7 +31,6 @@ func restoreIpAddresses(s string) []string {
 
 // 有效 IP 地址 正好由四个整数（每个整数位于 0 到 255 之间组成，且不能含有前导 0），整数之间用 '.' 分隔。
 func isValidIP(s string, start, end int) bool {
-	fmt.Println(s, start, end)
 	if start > end {
 		return false
 	}
@@ -46,13 +40,13 @@ func isValidIP(s string, start, end int) bool {
 		return false
 	}
 
-	var num uint8 = 0
+	var num = 0
 	for i := start; i <= end; i++ {
 		if s[i] > '9' || s[i] < '0' {
 			return false
 		}
 		// 累加
-		num = num*10 + (s[i] - '0')
+		num = num*10 + int(s[i]-'0')
 		if num > 255 {
 			return false
 		}