14. Longest Common Prefix

```Solution.c char* longestCommonPrefix(char** strs, int strsSize) { if(strsSize==0) return ""; char* prefix=strs[0]; for(int i=1;i<strsSize;i++){ int j=0; while(prefix[j] && strs[i][j] && prefix[j]==strs[i][j]){ j++; } prefix[j]='\0'; } return prefix; } ``` ```Solution.cpp class Solution { public: string longestCommonPrefix(vector<string>& strs) { if (strs.empty()) return ""; string prefix = strs[0]; for (int i = 1; i < strs.size(); ++i) { while (strs[i].find(prefix) != 0) prefix = prefix.substr(0, prefix.length() - 1); if (prefix.empty()) return ""; } return prefix; } }; ``` ```Solution.cs public class Solution { public string LongestCommonPrefix(string[] strs) { if (strs.Length == 0) return ""; string prefix = strs[0]; for (int i = 1; i < strs.Length; i++) { while (!strs[i].StartsWith(prefix)) { prefix = prefix.Substring(0, prefix.Length - 1); if (prefix == "") return ""; } } return prefix; } } ``` ```Solution.dart class Solution { String longestCommonPrefix(List<String> strs) { if (strs.isEmpty) return ""; String prefix = strs[0]; for (var str in strs.skip(1)) { while (!str.startsWith(prefix)) { prefix = prefix.substring(0, prefix.length - 1); if (prefix.isEmpty) return ""; } } return prefix; } } ``` ```Solution.erl -spec longest_common_prefix(Strs :: [unicode:unicode_binary()]) -> unicode:unicode_binary(). longest_common_prefix([]) -> <<>>; longest_common_prefix([Prefix | Rest]) -> longest_common_prefix(Rest, Prefix). longest_common_prefix([], Prefix) -> Prefix; longest_common_prefix([H | T], Prefix) -> longest_common_prefix(T, common_prefix(Prefix, H)). common_prefix(A, B) -> common_prefix(A, B, <<>>). common_prefix(<<>>, _, Acc) -> Acc; common_prefix(_, <<>>, Acc) -> Acc; common_prefix(<<H1:8, T1/binary>>, <<H2:8, T2/binary>>, Acc) when H1 =:= H2 -> common_prefix(T1, T2, <<Acc/binary, H1>>); common_prefix(_, _, Acc) -> Acc. ``` ```Solution.ex defmodule Solution do @SPEC longest_common_prefix(strs :: [String.t]) :: String.t def longest_common_prefix([]), do: "" def longest_common_prefix([head | tail]) do Enum.reduce(tail, head, fn str, acc -> common_prefix(acc, str) end) end defp common_prefix(str1, str2) do str1 |> String.graphemes() |> Enum.zip(String.graphemes(str2)) |> Enum.take_while(fn {c1, c2} -> c1 == c2 end) |> Enum.map(fn {c, _} -> c end) |> Enum.join() end end ``` ```Solution.go func longestCommonPrefix(strs []string) string { if len(strs) == 0 { return "" } prefix := strs[0] for _, s := range strs[1:] { for !strings.HasPrefix(s, prefix) { prefix = prefix[:len(prefix)-1] if prefix == "" { return "" } } } return prefix } ``` ```Solution.java class Solution { public String longestCommonPrefix(String[] strs) { if (strs.length == 0) return ""; String prefix = strs[0]; for (int i = 1; i < strs.length; i++) { while (strs[i].indexOf(prefix) != 0) { prefix = prefix.substring(0, prefix.length() - 1); if (prefix.isEmpty()) return ""; } } return prefix; } } ``` ```Solution.js /** * @param {string[]} strs * @return {string} */ var longestCommonPrefix = function(strs) { if (!strs.length) return ""; let prefix = strs[0]; for (let i = 1; i < strs.length; i++) { while (!strs[i].startsWith(prefix)) { prefix = prefix.slice(0, -1); if (!prefix) return ""; } } return prefix; }; ``` ```Solution.kt class Solution { fun longestCommonPrefix(strs: Array<String>): String { if (strs.isEmpty()) return "" var prefix = strs[0] for (str in strs.drop(1)) { while (!str.startsWith(prefix)) { prefix = prefix.dropLast(1) if (prefix.isEmpty()) return "" } } return prefix } } ``` ```Solution.php class Solution { /** * @param String[] $strs * @return String */ function longestCommonPrefix($strs) { if (empty($strs)) return ""; $prefix = $strs[0]; for ($i = 1; $i < count($strs); $i++) { while (strpos($strs[$i], $prefix) !== 0) { $prefix = substr($prefix, 0, -1); if ($prefix === "") return ""; } } return $prefix; } } ``` ```Solution.py class Solution: def longestCommonPrefix(self, strs: List[str]) -> str: if not strs: return "" prefix = strs[0] for s in strs[1:]: while not s.startswith(prefix): prefix = prefix[:-1] if not prefix: return "" return prefix ``` ```Solution.rb # @param {String[]} strs # @return {String} def longest_common_prefix(strs) return "" if strs.empty? prefix = strs[0] strs.each do |s| while !s.start_with?(prefix) prefix = prefix[0...-1] return "" if prefix.empty? end end prefix end ``` ```Solution.rkt (require racket/string) (define (longest-common-prefix strs) (if (null? strs) "" (let loop ((prefix (car strs)) (rest (cdr strs))) (cond [(null? rest) prefix] [else (define s (car rest)) (define (common p) (if (or (string=? p "") (string-prefix? s p)) p (common (substring p 0 (- (string-length p) 1))))) (loop (common prefix) (cdr rest))])))) ``` ```Solution.rs impl Solution { pub fn longest_common_prefix(strs: Vec<String>) -> String { if strs.is_empty() { return "".to_string(); } let mut prefix = strs[0].clone(); for s in strs.iter().skip(1) { while !s.starts_with(&prefix) { prefix.pop(); if prefix.is_empty() { return "".to_string(); } } } prefix } } ``` ```Solution.scala object Solution { def longestCommonPrefix(strs: Array[String]): String = { if (strs.isEmpty) return "" var prefix = strs(0) for(i <- 1 until strs.length) { while(!strs(i).startsWith(prefix) && prefix.nonEmpty) { prefix = prefix.substring(0,prefix.length-1) } } prefix } } ``` ```Solution.swift class Solution { func longestCommonPrefix(_ strs: [String]) -> String { if strs.isEmpty { return "" } var prefix = strs[0] for str in strs[1...] { while !str.hasPrefix(prefix) { prefix = String(prefix.dropLast()) if prefix.isEmpty { return "" } } } return prefix } } ``` ```Solution.ts function longestCommonPrefix(strs: string[]): string { if (strs.length === 0) return ""; let prefix = strs[0]; for (let i = 1; i < strs.length; i++) { while (!strs[i].startsWith(prefix)) { prefix = prefix.slice(0, -1); if (!prefix) return ""; } } return prefix; } ```

Author: nendroids

sol/solution/0001-0100/0014/README.md

@@ -0,0 +1,22 @@
+# [**14. Longest Common Prefix**](https://leetcode.com/problems/longest-common-prefix/description/)
+
+Write a function to find the longest common prefix string amongst an array of strings.<br>
+If there is no common prefix, return an empty string `""`.
+
+#### **Example 1:**
+```md
+Input: strs = ["flower","flow","flight"]
+Output: "fl"
+```
+
+#### **Example 2:**
+```md
+Input: strs = ["dog","racecar","car"]
+Output: ""
+Explanation: There is no common prefix among the input strings.
+```
+
+#### **Constraints:**
+> - `1 <= strs.length <= 200`
+> - `0 <= strs[i].length <= 200`
+> - `strs[i]` consists of only lowercase English letters if it is non-empty.

sol/solution/0001-0100/0014/Solution.c

@@ -0,0 +1,12 @@
+char* longestCommonPrefix(char** strs, int strsSize) {
+ if(strsSize==0) return "";
+ char* prefix=strs[0];
+ for(int i=1;i<strsSize;i++){
+ int j=0;
+ while(prefix[j] && strs[i][j] && prefix[j]==strs[i][j]){
+ j++;
+ }
+ prefix[j]='\0';
+ }
+ return prefix;
+}

sol/solution/0001-0100/0014/Solution.cpp

@@ -0,0 +1,13 @@
+class Solution {
+public:
+ string longestCommonPrefix(vector<string>& strs) {
+ if (strs.empty()) return "";
+ string prefix = strs[0];
+ for (int i = 1; i < strs.size(); ++i) {
+ while (strs[i].find(prefix) != 0)
+ prefix = prefix.substr(0, prefix.length() - 1);
+ if (prefix.empty()) return "";
+ }
+ return prefix;
+ }
+};

sol/solution/0001-0100/0014/Solution.cs

@@ -0,0 +1,13 @@
+public class Solution {
+ public string LongestCommonPrefix(string[] strs) {
+ if (strs.Length == 0) return "";
+ string prefix = strs[0];
+ for (int i = 1; i < strs.Length; i++) {
+ while (!strs[i].StartsWith(prefix)) {
+ prefix = prefix.Substring(0, prefix.Length - 1);
+ if (prefix == "") return "";
+ }
+ }
+ return prefix;
+ }
+}

sol/solution/0001-0100/0014/Solution.dart

@@ -0,0 +1,13 @@
+class Solution {
+ String longestCommonPrefix(List<String> strs) {
+ if (strs.isEmpty) return "";
+ String prefix = strs[0];
+ for (var str in strs.skip(1)) {
+ while (!str.startsWith(prefix)) {
+ prefix = prefix.substring(0, prefix.length - 1);
+ if (prefix.isEmpty) return "";
+ }
+ }
+ return prefix;
+ }
+}

sol/solution/0001-0100/0014/Solution.erl

@@ -0,0 +1,14 @@
+-spec longest_common_prefix(Strs :: [unicode:unicode_binary()]) -> unicode:unicode_binary().
+longest_common_prefix([]) -> <<>>;
+longest_common_prefix([Prefix | Rest]) ->
+ longest_common_prefix(Rest, Prefix).
+longest_common_prefix([], Prefix) -> Prefix;
+longest_common_prefix([H | T], Prefix) ->
+ longest_common_prefix(T, common_prefix(Prefix, H)).
+common_prefix(A, B) ->
+ common_prefix(A, B, <<>>).
+common_prefix(<<>>, _, Acc) -> Acc;
+common_prefix(_, <<>>, Acc) -> Acc;
+common_prefix(<<H1:8, T1/binary>>, <<H2:8, T2/binary>>, Acc) when H1 =:= H2 ->
+ common_prefix(T1, T2, <<Acc/binary, H1>>);
+common_prefix(_, _, Acc) -> Acc.

sol/solution/0001-0100/0014/Solution.ex

@@ -0,0 +1,17 @@
+defmodule Solution do
+ @spec longest_common_prefix(strs :: [String.t]) :: String.t
+ def longest_common_prefix([]), do: ""
+ def longest_common_prefix([head | tail]) do
+ Enum.reduce(tail, head, fn str, acc ->
+ common_prefix(acc, str)
+ end)
+ end
+ defp common_prefix(str1, str2) do
+ str1
+ |> String.graphemes()
+ |> Enum.zip(String.graphemes(str2))
+ |> Enum.take_while(fn {c1, c2} -> c1 == c2 end)
+ |> Enum.map(fn {c, _} -> c end)
+ |> Enum.join()
+ end
+end

sol/solution/0001-0100/0014/Solution.go

@@ -0,0 +1,15 @@
+func longestCommonPrefix(strs []string) string {
+ if len(strs) == 0 {
+ return ""
+ }
+ prefix := strs[0]
+ for _, s := range strs[1:] {
+ for !strings.HasPrefix(s, prefix) {
+ prefix = prefix[:len(prefix)-1]
+ if prefix == "" {
+ return ""
+ }
+ }
+ }
+ return prefix
+}

sol/solution/0001-0100/0014/Solution.java

@@ -0,0 +1,13 @@
+class Solution {
+ public String longestCommonPrefix(String[] strs) {
+ if (strs.length == 0) return "";
+ String prefix = strs[0];
+ for (int i = 1; i < strs.length; i++) {
+ while (strs[i].indexOf(prefix) != 0) {
+ prefix = prefix.substring(0, prefix.length() - 1);
+ if (prefix.isEmpty()) return "";
+ }
+ }
+ return prefix;
+ }
+}

sol/solution/0001-0100/0014/Solution.js

@@ -0,0 +1,15 @@
+/**
+ * @param {string[]} strs
+ * @return {string}
+ */
+var longestCommonPrefix = function(strs) {
+ if (!strs.length) return "";
+ let prefix = strs[0];
+ for (let i = 1; i < strs.length; i++) {
+ while (!strs[i].startsWith(prefix)) {
+ prefix = prefix.slice(0, -1);
+ if (!prefix) return "";
+ }
+ }
+ return prefix;
+};