FEAT: add longest_common_substring.go

go/42_dynamic_programming/longest_common_substring.go

@@ -0,0 +1,42 @@
+package main
+
+import "fmt"
+
+func lsc(s1 string, s2 string) int {
+	m := len(s1)
+	n := len(s2)
+
+	memo := make([][]int, m + 1)
+	for i := 0; i < m + 1; i++ {
+		memo[i] = make([]int, n + 1)
+	}
+
+
+	for i := 1; i < m + 1; i++ {
+		for j := 1; j < n + 1; j++ {
+			if s1[i - 1] == s2[j - 1] {
+				memo[i][j] = memo[i - 1][j - 1] + 1
+			}
+		}
+	}
+
+	fmt.Println(memo)
+	longest := 0
+	for i, _ := range memo {
+		for j, e2 := range memo[i] {
+			if longest < memo[i][j] {
+				longest = e2
+			}
+		}
+	}
+
+	return longest
+}
+
+func main() {
+	fmt.Println(lsc("blue", "clues"))	//3
+	fmt.Println(lsc("fosh", "fish"))	//2
+	fmt.Println(lsc("fosh", "fort"))	//2
+	fmt.Println(lsc("hish", "fish"))	//3
+	fmt.Println(lsc("hish", "vista"))	//2
+}