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# Count strings that end with the given pattern

• Difficulty Level : Easy
• Last Updated : 02 Jun, 2021

Given a pattern pat and a string array sArr[], the task is to count the number of strings from the array that ends with the given pattern.
Examples:

Input: pat = “ks”, sArr[] = {“geeks”, “geeksforgeeks”, “games”, “unit”}
Output:
Only string “geeks” and “geeksforgeeks” end with the pattern “ks”.
Input: pat = “abc”, sArr[] = {“abcd”, “abcc”, “aaa”, “bbb”}
Output:

Approach:

• Initialize count = 0 and start traversing the given string array.
• For every string str, initialize strLen = len(str) and patLen = len(pattern)
• If patLen > strLen then skips to the next string as the current string cannot end with the given pattern.
• Else match the string with the pattern starting from the end. If the string matches the pattern then update count = count + 1.
• Print the count in the end.

Below is the implementation of the above approach:

## C++

 `// C++ implementation of the approach``#include ``using` `namespace` `std;` `// Function that return true if str``// ends with pat``bool` `endsWith(string str, string pat)``{``    ``int` `patLen = pat.length();``    ``int` `strLen = str.length();` `    ``// Pattern is larger in length than``    ``// the string``    ``if` `(patLen > strLen)``        ``return` `false``;` `    ``// We match starting from the end while``    ``// patLen is greater than or equal to 0.``    ``patLen--;``    ``strLen--;``    ``while` `(patLen >= 0) {` `        ``// If at any index str doesn't match``        ``// with pattern``        ``if` `(pat[patLen] != str[strLen])``            ``return` `false``;``        ``patLen--;``        ``strLen--;``    ``}` `    ``// If str ends with the given pattern``    ``return` `true``;``}` `// Function to return the count of required``// strings``int` `countOfStrings(string pat, ``int` `n,``                       ``string sArr[])``{``    ``int` `count = 0;` `    ``for` `(``int` `i = 0; i < n; i++)` `        ``// If current string ends with``        ``// the given pattern``        ``if` `(endsWith(sArr[i], pat))``            ``count++;` `    ``return` `count;``}` `// Driver code``int` `main()``{` `    ``string pat = ``"ks"``;``    ``int` `n = 4;``    ``string sArr[] = { ``"geeks"``, ``"geeksforgeeks"``, ``"games"``, ``"unit"` `};` `    ``cout << countOfStrings(pat, n, sArr);` `    ``return` `0;``}`

## Java

 `// Java implementation of the approach``class` `GfG``{` `    ``// Function that return true``    ``// if str ends with pat``    ``static` `boolean` `endsWith(String str, String pat)``    ``{``        ``int` `patLen = pat.length();``        ``int` `strLen = str.length();``    ` `        ``// Pattern is larger in length``        ``// than the string``        ``if` `(patLen > strLen)``            ``return` `false``;``    ` `        ``// We match starting from the end while``        ``// patLen is greater than or equal to 0.``        ``patLen--;``        ``strLen--;``        ``while` `(patLen >= ``0``)``        ``{``    ` `            ``// If at any index str doesn't match``            ``// with pattern``            ``if` `(pat.charAt(patLen) != str.charAt(strLen))``                ``return` `false``;``            ``patLen--;``            ``strLen--;``        ``}``    ` `        ``// If str ends with the given pattern``        ``return` `true``;``    ``}``    ` `    ``// Function to return the``    ``// count of required strings``    ``static` `int` `countOfStrings(String pat, ``int` `n,``                        ``String sArr[])``    ``{``        ``int` `count = ``0``;``        ``for` `(``int` `i = ``0``; i < n; i++)``        ``{``    ` `            ``// If current string ends with``            ``// the given pattern``            ``if` `(endsWith(sArr[i], pat))``                ``count++;``        ``}``        ``return` `count;``    ``}` `    ``// Driver code``    ``public` `static` `void` `main(String []args)``    ``{``        ``String pat = ``"ks"``;``        ``int` `n = ``4``;``        ``String sArr[] = { ``"geeks"``, ``"geeksforgeeks"``, ``"games"``, ``"unit"` `};``        ``System.out.println(countOfStrings(pat, n, sArr));``    ``}``}``    ` `// This code is contributed by Rituraj Jain`

## Python3

 `# Python3 implementation of the approach` `# Function that return true if str1``# ends with pat``def` `endsWith(str1, pat):` `    ``patLen ``=` `len``(pat)``    ``str1Len ``=` `len``(str1)` `    ``# Pattern is larger in length``    ``# than the str1ing``    ``if` `(patLen > str1Len):``        ``return` `False` `    ``# We match starting from the end while``    ``# patLen is greater than or equal to 0.``    ``patLen ``-``=` `1``    ``str1Len ``-``=` `1``    ``while` `(patLen >``=` `0``):` `        ``# If at any index str1 doesn't match``        ``# with pattern``        ``if` `(pat[patLen] !``=` `str1[str1Len]):``            ``return` `False``        ``patLen ``-``=` `1``        ``str1Len ``-``=` `1``    ` `    ``# If str1 ends with the given pattern``    ``return` `True` `# Function to return the count of``# required str1ings``def` `countOfstr1ings(pat, n, sArr):` `    ``count ``=` `0` `    ``for` `i ``in` `range``(n):` `        ``# If current str1ing ends with``        ``# the given pattern``        ``if` `(endsWith(sArr[i], pat) ``=``=` `True``):``            ``count ``+``=` `1``    ``return` `count` `# Driver code``pat ``=` `"ks"``n ``=` `4``sArr``=` `[ ``"geeks"``, ``"geeksforgeeks"``,``                 ``"games"``, ``"unit"``]` `print``(countOfstr1ings(pat, n, sArr))` `# This code is contributed by``# Mohit kumar 29`

## C#

 `// C# implementation of the approach``using` `System;` `class` `GFG``{``    ` `// Function that return true if str``// ends with pat``static` `bool` `endsWith(``string` `str, ``string` `pat)``{``    ``int` `patLen = pat.Length;``    ``int` `strLen = str.Length;` `    ``// Pattern is larger in length than``    ``// the string``    ``if` `(patLen > strLen)``        ``return` `false``;` `    ``// We match starting from the end while``    ``// patLen is greater than or equal to 0.``    ``patLen--;``    ``strLen--;``    ``while` `(patLen >= 0)``    ``{` `        ``// If at any index str doesn't match``        ``// with pattern``        ``if` `(pat[patLen] != str[strLen])``            ``return` `false``;``        ``patLen--;``        ``strLen--;``    ``}` `    ``// If str ends with the given pattern``    ``return` `true``;``}` `// Function to return the count of required``// strings``static` `int` `countOfStrings(``string` `pat, ``int` `n,``                        ``string``[] sArr)``{``    ``int` `count = 0;` `    ``for` `(``int` `i = 0; i < n; i++)` `        ``// If current string ends with``        ``// the given pattern``        ``if` `(endsWith(sArr[i], pat))``            ``count++;` `    ``return` `count;``}` `// Driver code``public` `static` `void` `Main()``{` `    ``string` `pat = ``"ks"``;``    ``int` `n = 4;``    ``string``[] sArr = { ``"geeks"``, ``"geeksforgeeks"``,``                                ``"games"``, ``"unit"` `};``    ``Console.WriteLine(countOfStrings(pat, n, sArr));``}``}` `// This code is contributed by Akanksha Rai`

## PHP

 ` ``\$strLen``)``        ``return` `false;` `    ``// We match starting from the end while``    ``// patLen is greater than or equal to 0.``    ``\$patLen``--;``    ``\$strLen``--;``    ``while` `(``\$patLen` `>= 0)``    ``{` `        ``// If at any index str doesn't match``        ``// with pattern``        ``if` `(``\$pat``[``\$patLen``] != ``\$str``[``\$strLen``])``            ``return` `false;``        ``\$patLen``--;``        ``\$strLen``--;``    ``}` `    ``// If str ends with the given pattern``    ``return` `true;``}` `// Function to return the count of required``// strings``function` `countOfStrings(``\$pat``, ``\$n``, ``\$sArr``)``{``    ``\$count` `= 0;` `    ``for` `(``\$i` `= 0; ``\$i` `< ``\$n``; ``\$i``++)` `        ``// If current string ends with``        ``// the given pattern``        ``if` `(endsWith(``\$sArr``[``\$i``], ``\$pat``))``            ``\$count``++;` `    ``return` `\$count``;``}` `// Driver code``\$pat` `= ``"ks"``;``\$n` `= 4;``\$sArr` `= ``array``(``"geeks"``, ``"geeksforgeeks"``,``              ``"games"``, ``"unit"``);` `echo` `countOfStrings(``\$pat``, ``\$n``, ``\$sArr``);` `// This code is contributed by mits``?>`

## Javascript

 ``
Output:
`2`

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