438. Find All Anagrams in a String

Author: kimi0230

Leetcode/0438.Find-All-Anagrams-in-a-String/README.md

@@ -1,6 +1,6 @@
 ---
 title: Find All Anagrams in a String
-tags: Medium
+tags: Medium, Sliding Window
 author: Kimi Tsai <[email protected]>
 description:
 ---
@@ -36,8 +36,9 @@ s and p consist of lowercase English letters.
 
 ## 題目大意
 找所有字母異位詞, 就像[全排列](https://github.com/kimi0230/LeetcodeGolang/blob/master/Leetcode/0567.Permutation-in-String/main.go)
-
+給定一個字符串 S 和非空的字符串 P, 找到 S 中所有是 P 得排列, 並返回他的起始 index
 ## 解題思路
+跟 [0567.Permutation-in-String](https://github.com/kimi0230/LeetcodeGolang/blob/master/Leetcode/0567.Permutation-in-String/main.go)類似, 只是把找到的答案記錄起來
 
 ## 來源
 * https://leetcode.com/problems/find-all-anagrams-in-a-string/

Leetcode/0438.Find-All-Anagrams-in-a-String/main.go

@@ -0,0 +1,75 @@
+package findallanagramsinastring
+
+func FindAnagrams(s string, p string) []int {
+	need, window := make(map[rune]int), make(map[rune]int)
+	for _, c := range p {
+		need[c]++
+	}
+
+	left, right := 0, 0
+	valid := 0
+	res := []int{} //紀錄結果
+	for right < len(s) {
+		c := rune(s[right])
+		right++
+
+		if need[c] > 0 {
+			window[c]++
+			if window[c] == need[c] {
+				valid++
+			}
+		}
+		// fmt.Printf("[%d,%d) \n", left, right)
+
+		// 判斷左視窗是否收縮, 看看視窗長度是否同要找的字串的長度
+		if (right - left) >= len(p) {
+			if valid == len(need) {
+				// 想要的字元都找到了, 紀錄index
+				res = append(res, left)
+			}
+			d := rune(s[left])
+			left++
+			if need[d] > 0 {
+				if window[d] == need[d] {
+					valid--
+				}
+				window[d]--
+			}
+		}
+	}
+	return res
+}
+
+// 用 slice 取代 map 來優化
+func FindAnagramsSlice(s string, p string) []int {
+	need := [256]int{}
+	for _, c := range p {
+		need[c-'a']++
+	}
+	left, right := 0, 0
+	count := len(p)
+	res := []int{}
+
+	for right < len(s) {
+		c := s[right] - 'a'
+		if need[c] > 0 {
+			count--
+		}
+		need[c]--
+		right++
+
+		if count == 0 {
+			res = append(res, left)
+		}
+
+		if (right - left) >= len(p) {
+			d := s[left] - 'a'
+			if need[d] >= 0 {
+				count++
+			}
+			need[d]++
+			left++
+		}
+	}
+	return res
+}

Leetcode/0438.Find-All-Anagrams-in-a-String/main_test.go

@@ -0,0 +1,65 @@
+package findallanagramsinastring
+
+import (
+	"reflect"
+	"testing"
+)
+
+var tests = []struct {
+	arg1 string
+	arg2 string
+	want []int
+}{
+	{
+		"cbaebabacd",
+		"abc",
+		[]int{0, 6},
+	},
+	{
+		"abab",
+		"ab",
+		[]int{0, 1, 2},
+	},
+}
+
+func TestFindAnagrams(t *testing.T) {
+	for _, tt := range tests {
+		if got := FindAnagrams(tt.arg1, tt.arg2); !reflect.DeepEqual(got, tt.want) {
+			t.Errorf("got = %v, want = %v", got, tt.want)
+		}
+	}
+}
+
+func TestFindAnagramsSlice(t *testing.T) {
+	for _, tt := range tests {
+		if got := FindAnagramsSlice(tt.arg1, tt.arg2); !reflect.DeepEqual(got, tt.want) {
+			t.Errorf("got = %v, want = %v", got, tt.want)
+		}
+	}
+}
+
+func BenchmarkFindAnagrams(b *testing.B) {
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		FindAnagrams(tests[0].arg1, tests[0].arg2)
+	}
+}
+
+func BenchmarkFindAnagramsSlice(b *testing.B) {
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		FindAnagramsSlice(tests[0].arg1, tests[0].arg2)
+	}
+}
+
+/*
+go test -benchmem -run=none LeetcodeGolang/Leetcode/0438.Find-All-Anagrams-in-a-String -bench=.
+goos: darwin
+goarch: amd64
+pkg: LeetcodeGolang/Leetcode/0438.Find-All-Anagrams-in-a-String
+cpu: Intel(R) Core(TM) i5-8259U CPU @ 2.30GHz
+BenchmarkFindAnagrams-8          1572444               690.4 ns/op            24 B/op          2 allocs/op
+BenchmarkFindAnagramsSlice-8    11687409               136.9 ns/op            24 B/op          2 allocs/op
+PASS
+ok      LeetcodeGolang/Leetcode/0438.Find-All-Anagrams-in-a-String      4.329s
+*/

Leetcode/0567.Permutation-in-String/README.md

@@ -1,3 +1,9 @@
+---
+title: Permutation in String
+tags: Medium, Sliding Window
+author: Kimi Tsai <[email protected]>
+description:
+---
 # [567. Permutation in String](https://leetcode.com/problems/permutation-in-string/)
 tags: Medium, Sliding Window
 

README.md

@@ -164,6 +164,7 @@ void slidingWindow(string s, string t){
 | No. | Title | Solution | Difficulty | Time | Space | Topic |
 |-----|:-----:|:--------:|------------|------|-------|-------|
 | 0209 | [Minimum Size Subarray Sum](https://leetcode.com/problems/minimum-size-subarray-sum/) | [Go](https://github.com/kimi0230/LeetcodeGolang/tree/master/Leetcode/0209.Minimum-Size-Subarray-Sum) | Medium | O(n^2) / O(n) / O(nlog n) |  O(1) / O(1) / O(n) | Sliding Window |
+| 0438 | [438. Find All Anagrams in a String](https://leetcode.com/problems/find-all-anagrams-in-a-string/) | [Go](https://github.com/kimi0230/LeetcodeGolang/tree/master/Leetcode/0438.Find-All-Anagrams-in-a-String) | Medium | O(n) |  O(1) | Sliding Window |
 | 0567 | [Permutation in String](https://leetcode.com/problems/permutation-in-string/) | [Go](https://github.com/kimi0230/LeetcodeGolang/tree/master/Leetcode/0567.Permutation-in-String) | Medium | O(n) |  O(1) | Sliding Window |
 
 ---