From 2896eb758971260f5ae446b8c8ef5303b3a326f9 Mon Sep 17 00:00:00 2001
From: rulanugrh <nextarituenak01@gmail.com>
Date: Tue, 12 Mar 2024 16:18:15 +0700
Subject: [PATCH] feat: adding testing for kmp algorithm

---
 algorithm/algorithm_test.go |  16 ++++++
 algorithm/kmp.go            | 105 ++++++++++++++++++++++++++++++++++++
 2 files changed, 121 insertions(+)
 create mode 100644 algorithm/kmp.go

diff --git a/algorithm/algorithm_test.go b/algorithm/algorithm_test.go
index e438308..a16f720 100644
--- a/algorithm/algorithm_test.go
+++ b/algorithm/algorithm_test.go
@@ -12,3 +12,19 @@ func TestCompressLZW(t *testing.T) {
 
 	assert.Equal(t, expected, str)
 }
+
+func TestKMP(t *testing.T) {
+  str := SearchString("syahara", "sy")
+
+  assert.Equal(t, 0, str)
+}
+
+func TestKMPLast(t *testing.T) {
+  str := SerchNext("syahara", "ha")
+  assert.Equal(t, 3, str)
+}
+
+func TestKMPNone(t *testing.T) {
+  str := SearchString("araa", "rul")
+  assert.Equal(t, -1, str)
+}
diff --git a/algorithm/kmp.go b/algorithm/kmp.go
new file mode 100644
index 0000000..082e613
--- /dev/null
+++ b/algorithm/kmp.go
@@ -0,0 +1,105 @@
+package algorithm
+
+
+const (
+	PatternSize int = 100
+)
+
+func SerchNext(stack string, needle string) int {
+  ret := KMP(stack, needle)
+  if len(ret) > 0 {
+    return ret[len(ret)-1]
+  }
+
+  return -1
+}
+
+func SearchString(stack string, needle string) int {
+
+	ret := KMP(stack, needle)
+	if len(ret) > 0 {
+		return ret[0]
+	}
+
+	return -1
+}
+
+func KMP(stack string, needle string) []int {
+	next := preKMP(needle)
+	i := 0
+	j := 0
+	m := len(needle)
+	n := len(stack)
+
+	x := []byte(needle)
+	y := []byte(stack)
+	var ret []int
+
+	if m == 0 || n == 0 {
+		return ret
+	}
+
+	if n < m {
+		return ret
+	}
+
+	for j < n {
+		for i > -1 && x[i] != y[j] {
+			i = next[i]
+		}
+		i++
+		j++
+
+		if i >= m {
+			ret = append(ret, j-i)
+			i = next[i]
+		}
+	}
+
+	return ret
+}
+func preMP(x string) [PatternSize]int {
+	var i, j int
+	lenght := len(x) - 1
+
+	var mpNext [PatternSize]int
+	i = 0
+	j = -1
+	mpNext[0] = -1
+
+	for i < lenght {
+		for j > -1 && x[i] != x[j] {
+			j = mpNext[j]
+		}
+		i++
+		j++
+		mpNext[i] = j
+	}
+
+	return mpNext
+}
+
+func preKMP(x string) [PatternSize]int {
+	var i, j int
+	lenght := len(x) - 1
+
+	var kmpNext [PatternSize]int
+	i = 0
+	j = -1
+	kmpNext[0] = -1
+
+	for i < lenght {
+		for j > -1 && x[i] != x[j] {
+			j = kmpNext[j]
+		}
+		i++
+		j++
+
+		if x[i] == x[j] {
+			kmpNext[i] = kmpNext[j]
+		} else {
+			kmpNext[i] = j
+		}
+	}
+	return kmpNext
+}