Data commit

Task/Longest-common-subsequence/Go/longest-common-subsequence-1.go

@@ -0,0 +1,15 @@
+func lcs(a, b string) string {
+    aLen := len(a)
+    bLen := len(b)
+    if aLen == 0 || bLen == 0 {
+        return ""
+    } else if a[aLen-1] == b[bLen-1] {
+        return lcs(a[:aLen-1], b[:bLen-1]) + string(a[aLen-1])
+    }
+    x := lcs(a, b[:bLen-1])
+    y := lcs(a[:aLen-1], b)
+    if len(x) > len(y) {
+        return x
+    }
+    return y
+}

Task/Longest-common-subsequence/Go/longest-common-subsequence-2.go

@@ -0,0 +1,42 @@
+func lcs(a, b string) string {
+	arunes := []rune(a)
+	brunes := []rune(b)
+	aLen := len(arunes)
+	bLen := len(brunes)
+	lengths := make([][]int, aLen+1)
+	for i := 0; i <= aLen; i++ {
+		lengths[i] = make([]int, bLen+1)
+	}
+	// row 0 and column 0 are initialized to 0 already
+
+	for i := 0; i < aLen; i++ {
+		for j := 0; j < bLen; j++ {
+			if arunes[i] == brunes[j] {
+				lengths[i+1][j+1] = lengths[i][j] + 1
+			} else if lengths[i+1][j] > lengths[i][j+1] {
+				lengths[i+1][j+1] = lengths[i+1][j]
+			} else {
+				lengths[i+1][j+1] = lengths[i][j+1]
+			}
+		}
+	}
+
+	// read the substring out from the matrix
+	s := make([]rune, 0, lengths[aLen][bLen])
+	for x, y := aLen, bLen; x != 0 && y != 0; {
+		if lengths[x][y] == lengths[x-1][y] {
+			x--
+		} else if lengths[x][y] == lengths[x][y-1] {
+			y--
+		} else {
+			s = append(s, arunes[x-1])
+			x--
+			y--
+		}
+	}
+	// reverse string
+	for i, j := 0, len(s)-1; i < j; i, j = i+1, j-1 {
+		s[i], s[j] = s[j], s[i]
+	}
+	return string(s)
+}