Merge pull request halfrost#217 from brenobaptista/update-14

Update problem halfrost#14

Author: halfrost

leetcode/0014.Longest-Common-Prefix/14.Longest Common Prefix.go

@@ -1,23 +1,16 @@
 package leetcode
 
-import "sort"
-
 func longestCommonPrefix(strs []string) string {
-	sort.Slice(strs, func(i, j int) bool {
-		return len(strs[i]) <= len(strs[j])
-	})
-	minLen := len(strs[0])
-	if minLen == 0 {
-		return ""
-	}
-	var commonPrefix []byte
-	for i := 0; i < minLen; i++ {
-		for j := 1; j < len(strs); j++ {
-			if strs[j][i] != strs[0][i] {
-				return string(commonPrefix)
+	prefix := strs[0]
+
+	for i := 1; i < len(strs); i++ {
+		for j := 0; j < len(prefix); j++ {
+			if len(strs[i]) <= j || strs[i][j] != prefix[j] {
+				prefix = prefix[0:j]
+				break
 			}
 		}
-		commonPrefix = append(commonPrefix, strs[0][i])
 	}
-	return string(commonPrefix)
+
+	return prefix
 }

leetcode/0014.Longest-Common-Prefix/14.Longest Common Prefix_test.go

@@ -33,6 +33,11 @@ func Test_Problem14(t *testing.T) {
 			para14{[]string{"dog", "racecar", "car"}},
 			ans14{""},
 		},
+
+		{
+			para14{[]string{"ab", "a"}},
+			ans14{"a"},
+		},
 	}
 
 	fmt.Printf("------------------------Leetcode Problem 14------------------------\n")

leetcode/0014.Longest-Common-Prefix/README.md

@@ -40,25 +40,18 @@ If there is no common prefix, return an empty string "".
 
 package leetcode
 
-import "sort"
-
 func longestCommonPrefix(strs []string) string {
-	sort.Slice(strs, func(i, j int) bool {
-		return len(strs[i]) <= len(strs[j])
-	})
-	minLen := len(strs[0])
-	if minLen == 0 {
-		return ""
-	}
-	var commonPrefix []byte
-	for i := 0; i < minLen; i++ {
-		for j := 1; j < len(strs); j++ {
-			if strs[j][i] != strs[0][i] {
-				return string(commonPrefix)
+	prefix := strs[0]
+
+	for i := 1; i < len(strs); i++ {
+		for j := 0; j < len(prefix); j++ {
+			if len(strs[i]) <= j || strs[i][j] != prefix[j] {
+				prefix = prefix[0:j]
+				break
 			}
 		}
-		commonPrefix = append(commonPrefix, strs[0][i])
 	}
-	return string(commonPrefix)
+
+	return prefix
 }
-```
+```