diff --git a/diff/diff.go b/diff/diff.go
index 534f454..9fcb02b 100644
--- a/diff/diff.go
+++ b/diff/diff.go
@@ -53,7 +53,7 @@ func Diff(o, n []string) []Instruction {
 	maxl := 0
 	omax := 0
 	nmax := 0
-	matrix := make(map[int]map[int]int, len(o)+1)
+	matrix := make(map[twoints]int, len(o)+1)
 
 	for oindex, ovalue := range o {
 
@@ -66,14 +66,11 @@ func Diff(o, n []string) []Instruction {
 		}
 
 		// Build diff matrix
-		for nindex, _ := range nkeys {
-			if _, ok := matrix[oindex]; !ok {
-				matrix[oindex] = make(map[int]int, len(n)+1)
-			}
-			matrix[oindex][nindex] = matrix[oindex-1][nindex-1] + 1
+		for _, nindex := range nkeys {
+			matrix[twoints{oindex, nindex}] = matrix[twoints{oindex - 1, nindex - 1}] + 1
 
-			if matrix[oindex][nindex] > maxl {
-				maxl = matrix[oindex][nindex]
+			if matrix[twoints{oindex, nindex}] > maxl {
+				maxl = matrix[twoints{oindex, nindex}]
 				omax = oindex + 1 - maxl
 				nmax = nindex + 1 - maxl
 			}
@@ -87,7 +84,7 @@ func Diff(o, n []string) []Instruction {
 		}
 	}
 
-	ret := Diff(o[0:omax], n[0:nmax])
+	ret := Diff(o[:omax], n[:nmax])
 	if maxl != nmax {
 		ret = append(ret, Instruction{OP_UNCHANGED, n[nmax : maxl-nmax]})
 	}