vendor tsgo

tools/tsgo/vendor/github.com/peter-evans/patience/lcs.go

@@ -0,0 +1,54 @@
+// Package patience implements the Patience Diff algorithm.
+package patience
+
+// LCS computes the longest common subsequence of two string
+// slices and returns the index pairs of the LCS.
+func LCS(a, b []string) [][2]int {
+	// Initialize the LCS table.
+	lcs := make([][]int, len(a)+1)
+	for i := 0; i <= len(a); i++ {
+		lcs[i] = make([]int, len(b)+1)
+	}
+
+	// Populate the LCS table.
+	for i := 1; i < len(lcs); i++ {
+		for j := 1; j < len(lcs[i]); j++ {
+			if a[i-1] == b[j-1] {
+				lcs[i][j] = lcs[i-1][j-1] + 1
+			} else {
+				lcs[i][j] = max(lcs[i-1][j], lcs[i][j-1])
+			}
+		}
+	}
+
+	// Backtrack to find the LCS.
+	i, j := len(a), len(b)
+	s := make([][2]int, 0, lcs[i][j])
+	for i > 0 && j > 0 {
+		switch {
+		case a[i-1] == b[j-1]:
+			s = append(s, [2]int{i - 1, j - 1})
+			i--
+			j--
+		case lcs[i-1][j] > lcs[i][j-1]:
+			i--
+		default:
+			j--
+		}
+	}
+
+	// Reverse the backtracked LCS.
+	for i, j := 0, len(s)-1; i < j; i, j = i+1, j-1 {
+		s[i], s[j] = s[j], s[i]
+	}
+
+	return s
+}
+
+// max returns the maximum of two integers.
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}