enhance code and stash KnuthMorrisPratt

Author: TTWShell

string/matching/string-matching.go

@@ -30,7 +30,29 @@ func Naive(s, txt string) bool {
 	if lentxt > lens {
 		return false
 	}
-	for i := 0; i < lens-lentxt; i++ {
+	for i := 0; i <= lens-lentxt; i++ {
+		for j := 0; j <= lentxt; j++ {
+			if j == lentxt {
+				return true
+			}
+			if txt[j] != s[i+j] {
+				break
+			}
+		}
+	}
+	return false
+}
+
+/*
+Knuth-Morris-Pratt 字符串匹配算法（即 KMP 算法）
+http://www.ruanyifeng.com/blog/2013/05/Knuth%E2%80%93Morris%E2%80%93Pratt_algorithm.html
+*/
+func KnuthMorrisPratt(s, txt string) bool {
+	lens, lentxt := len(s), len(txt)
+	if lentxt > lens {
+		return false
+	}
+	for i := 0; i <= lens-lentxt; i++ {
 		for j := 0; j <= lentxt; j++ {
 			if j == lentxt {
 				return true

string/matching/string-matching_test.go

@@ -8,7 +8,19 @@ func Test_Naive(t *testing.T) {
 	result := []bool{true, false, false, true}
 	for i := 0; i < len(sList); i++ {
 		if Naive(sList[i], txtList[i]) != result[i] {
-			t.Log(sList[i], txtList[i], result[i])
+			t.Log(sList[i], txtList[i], result[i], "result is:", Naive(sList[i], txtList[i]))
+			t.Fail()
+		}
+	}
+}
+
+func Test_KnuthMorrisPratt(t *testing.T) {
+	sList := []string{"BBC ABCDAB ABCDABCDABDE", "", "ab", "abc"}
+	txtList := []string{"ABCDABD", "a", "c", "c"}
+	result := []bool{true, false, false, true}
+	for i := 0; i < len(sList); i++ {
+		if KnuthMorrisPratt(sList[i], txtList[i]) != result[i] {
+			t.Log(sList[i], txtList[i], result[i], "result is:", KnuthMorrisPratt(sList[i], txtList[i]))
 			t.Fail()
 		}
 	}