Check if both halves of the string have at least one different character

Earlier we have discussed on how to check if both halves of the string have same set of characters. Now, we further extend our problem on checking if both halves of the string have at least one different character.

Examples: 

Input : baaaab
Output: No, both halves do not differ at all
The two halves contain the same characters and their frequencies match so not different the character exists

Input : abccpb
Output : Yes, both halves differ by at least one character

Method 1: (Two counter arrays)

• Split the string into two halves
• Traverse two different halves separately and count the occurrence of each character into two different counter array
• Now, traverse these arrays, and the if these array differ at a point, we get the answer as “Yes” 

Implementation:

C++

// C++ implementation to check if
// both halves of the string have
// at least one different character
#include <cstring>
#include <iostream>
#include <string>
using namespace std;
# define MAX 26

// Function which break string into two halves
// Counts frequency of characters in each half
// Compares the two counter array and returns
// true if these counter arrays differ
bool function(string str)
{
    int l = str.length();

    // Declaration and initialization
    // of counter array
    int counter1[MAX];
    int counter2[MAX];
    memset(counter1, 0, sizeof(counter1));
    memset(counter2, 0, sizeof(counter2));

    for (int i = 0; i < l / 2; i++)
        counter1[str[i] - 'a']++;
    for (int i = l / 2; i < l; i++)
        counter2[str[i] - 'a']++;
    for (int i = 0; i < MAX; i++)
        if (counter2[i] != counter1[i])
            return true;

    return false;
}

// Driver function
int main()
{
    string str = "abcasdsabcae";
    if (function(str))
        cout << "Yes, both halves differ"
             <<" by at least one character";
    else
        cout << "No, both halves do "
             <<"not differ at all";
    return 0;
}

Java

// Java implementation of the problem
import java.util.*;
import java.lang.*;

class GeeksforGeeks {
    final static int MAX = 26;

    // Function which break string into two halves
    // Counts frequency of characters in each half
    // Compares the two counter array and returns
    // true if these counter arrays differ
    static boolean function(String str)
    {
        int l = str.length();

        // Declaration and initialization
        // of counter array
        int counter1[] = new int[MAX];
        int counter2[] = new int[MAX];
        for (int i = 0; i < MAX; i++) {
            counter1[i] = 0;
            counter2[i] = 0;
        }

        for (int i = 0; i < l / 2; i++)
            counter1[str.charAt(i) - 'a']++;
        for (int i = l / 2; i < l; i++)
            counter2[str.charAt(i) - 'a']++;
        for (int i = 0; i < MAX; i++) {
            if (counter2[i] != counter1[i])
                return true;
        }
        return false;
    }

    // Driver function
    public static void main(String args[])
    {
        String str = "abcasdsabcae";
        if (function(str))
            System.out.print("Yes, both halves "+
            "differ by at least one character");
        else
            System.out.print("No, both halves "+
            "do not differ at all");
    }
}

Python3

# Python implementation to check if
# both halves of the string have
# at least one different character

MAX = 26

# Function which break string into two halves
# Counts frequency of characters in each half
# Compares the two counter array and returns
# true if these counter arrays differ
def function(st):
    global MAX
    l = len(st)

    # Declaration and initialization
    # of counter array
    counter1, counter2 = [0] * MAX, [0] * MAX

    for i in range(l//2):
        counter1[ord(st[i]) - ord('a')] += 1

    for i in range(l//2, l):
        counter2[ord(st[i]) - ord('a')] += 1

    for i in range(MAX):
        if (counter2[i] != counter1[i]):
            return True
    return False


# Driver function
st = "abcasdsabcae"
if function(st): print("Yes, both halves differ ",
                       "by at least one character")
else: print("No, both halves do not differ at all")

# This code is contributed by Ansu Kumari

C#

// C# implementation to check if
// both halves of the string have
// at least one different character


using System;

class GeeksforGeeks {
    static int MAX = 26;

    // Function which break string into two halves
    // Counts frequency of characters in each half
    // Compares the two counter array and returns
    // true if these counter arrays differ
    static bool function(String str)
    {
        int l = str.Length;

        // Declaration and initialization
        // of counter array
        int []counter1 = new int[MAX];
        int []counter2 = new int[MAX];
        for (int i = 0; i < MAX; i++)
        {
            counter1[i] = 0;
            counter2[i] = 0;
        }

        for (int i = 0; i < l / 2; i++)
            counter1[str[i] - 'a']++;
        for (int i = l / 2; i < l; i++)
            counter2[str[i] - 'a']++;
        for (int i = 0; i < MAX; i++) {
            if (counter2[i] != counter1[i])
                return true;
        }
        return false;
    }

    // Driver function
    public static void Main()
    {
        String str = "abcasdsabcae";
        if (function(str))
            Console.WriteLine("Yes, both halves "+
            "differ by at least one character");
        else
            Console.WriteLine("No, both halves "+
            "do not differ at all");
    }
}

//This code is contributed by vt_m.

PHP

<?php
// PHP implementation to check if
// both halves of the string have
// at least one different character

$MAX = 26;

// Function which break string into two halves
// Counts frequency of characters in each half
// Compares the two counter array and returns
// true if these counter arrays differ
function function_1($str)
{
    global $MAX;
    $l = strlen($str);

    // Declaration and initialization
    // of counter array
    $counter1 = array_fill(0,$MAX,NULL);
    $counter2 = array_fill(0,$MAX,NULL);

    for ($i = 0; $i < $l / 2; $i++)
        $counter1[ord($str[$i]) - ord('a')]++;
    for ($i = $l / 2; $i < $l; $i++)
        $counter2[ord($str[$i]) - ord('a')]++;
    for ($i = 0; $i < $MAX; $i++)
        if ($counter2[$i] != $counter1[$i])
            return true;

    return false;
}

// Driver function

$str = "abcasdsabcae";
if (function_1($str))
    echo "Yes, both halves differ"
         ." by at least one character";
else
    echo "No, both halves do "
         ."not differ at all";
return 0;
?>

Javascript

<script>

// JavaScript program implementation of the problem

let MAX = 26;

    // Function which break string into two halves
    // Counts frequency of characters in each half
    // Compares the two counter array and returns
    // true if these counter arrays differ
    function functions(str)
    {
        let l = str.length;

        // Declaration and initialization
        // of counter array
        let counter1 = [];
        let counter2 = [];
        for (let i = 0; i < MAX; i++)
        {
            counter1[i] = 0;
            counter2[i] = 0;
        }

        for (let i = 0; i < l / 2; i++)
            counter1[str[i] - 'a']++;
        for (let i = l / 2; i < l; i++)
            counter2[str[i] - 'a']++;
        for (let i = 0; i < MAX; i++) {
            if (counter2[i] != counter1[i])
                return true;
        }
        return false;
    }

// Driver code

        let str = "abcasdsabcae";
        if (functions(str) != 1)
            document.write("Yes, both halves "+
            "differ by at least one character");
        else
            document.write("No, both halves "+
            "do not differ at all");


</script>

Output

Yes, both halves differ by at least one character

Time Complexity: O(N), as we are using a loop to traverse N times. Where N is the length of the string.
Auxiliary Space: O(26), as we are using extra space for counter arrays.

Method 2:(One counter array)

• This method uses only a single array of length 26.
• For the first half, we increment the characters in the counter array of length 26.
• For second array, we decrement the character in that same counter array.
• Now, if for an index corresponding to a character has non-zero value, that is the distinct character present
• The positive ones are ones present in the first half and the negative ones are characters in the second half

Implementation:

C++

// C++ implementation to check if
// both halves of the string have
// at least one different character
#include <cstring>
#include <iostream>
#include <string>
using namespace std;
# define MAX 26

// Function which break string into two halves
// Increments frequency of characters for first half
// Decrements frequency of characters for second half
// true if any index has non-zero value
bool function(string str)
{
    int l = str.length();

    // Declaration and initialization
    // of counter array
    int counter[MAX];
    memset(counter, 0, sizeof(counter));
    for (int i = 0; i < l / 2; i++)
        counter[str[i] - 'a']++;
    for (int i = l / 2; i < l; i++)
        counter[str[i] - 'a']--;
    for (int i = 0; i < MAX; i++)
        if (counter[i] != 0)
            return true;

    return false;
}

// Driver function
int main()
{
    string str = "abcasdsabcae";
    if (function(str))
        cout << "Yes, both halves differ"
             <<" by at least one character";
    else
        cout << "No, both halves do"
             <<" not differ at all";
    return 0;
}

Java

// Java implementation of the problem
import java.util.*;
import java.lang.*;

class GeeksforGeeks {

    final static int MAX = 26;

    // Function which break string into two halves
    // Increments frequency of characters for first half
    // Decrements frequency of characters for second half
    // true if any index has non-zero value
    static boolean function(String str)
    {
        int l = str.length();

        // Declaration and initialization
        // of counter array
        int counter[] = new int[MAX];
        for (int i = 0; i < MAX; i++)
            counter[i] = 0;
        for (int i = 0; i < l / 2; i++)
            counter[str.charAt(i) - 'a']++;
        for (int i = l / 2; i < l; i++)
            counter[str.charAt(i) - 'a']--;
        for (int i = 0; i < MAX; i++)
            if (counter[i] != 0)
                return true;

        return false;
    }

    // Driver function
    public static void main(String args[])
    {
        String str = "abcasdsabcae";
        if (function(str))
            System.out.print("Yes, both halves"
            +" differ by at least one character");
        else
            System.out.print("No, both halves"
            +" do not differ at all");
    }
}

Python3

# Python3 implementation to check if
# both halves of the string have
# at least one different character
MAX = 26

# Function which break string into two
# halves Increments frequency of characters
# for first half Decrements frequency of
# characters for second half true if any
# index has non-zero value
def function(st):
    global MAX
    l = len(st)

    # Declaration and initialization
    # of counter array
    counter = [0] * MAX

    for i in range(l // 2):
        counter[ord(st[i]) - ord('a')] += 1

    for i in range(l // 2, l):
        counter[ord(st[i]) - ord('a')] -= 1

    for i in range(MAX):
        if (counter[i] != 0):
            return True

    return False

# Driver function
st = "abcasdsabcae"
if function(st):
    print("Yes, both halves differ by at ",
          "least one character")
else:
    print("No, both halves do not differ at all")

# This code is contributed by Ansu Kumari

C#

// C# implementation of the problem
using System;

class GFG {

    static int MAX = 26;

    // Function which break string into
    // two halves Increments frequency
    // of characters for first half
    // Decrements frequency of characters
    // for second half true if any index
    // has non-zero value
    static bool function(String str)
    {
        int l = str.Length;

        // Declaration and initialization
        // of counter array
        int []counter = new int[MAX];
        for (int i = 0; i < MAX; i++)
            counter[i] = 0;
        for (int i = 0; i < l / 2; i++)
            counter[str[i] - 'a']++;
        for (int i = l / 2; i < l; i++)
            counter[str[i] - 'a']--;
        for (int i = 0; i < MAX; i++)
            if (counter[i] != 0)
                return true;

        return false;
    }

    // Driver function
    public static void Main()
    {
        string str = "abcasdsabcae";
        if (function(str))
        Console.Write("Yes, both halves"
            + " differ by at least one "
                         + "character");
        else
            Console.Write("No, both halves"
              + " do not differ at all");
    }
}

// This code is contributed by anuj_67.

Javascript

<script>
// Javascript implementation of the problem

    let MAX = 26;

    // Function which break string into two halves
    // Increments frequency of characters for first half
    // Decrements frequency of characters for second half
    // true if any index has non-zero value
    function Function(str)
    {
        let l = str.length;

        // Declaration and initialization
        // of counter array
        let counter = new Array(MAX);
        for (let i = 0; i < MAX; i++)
            counter[i] = 0;
        for (let i = 0; i < l / 2; i++)
            counter[str[i].charCodeAt(0) - 'a'.charCodeAt(0)]++;
        for (let i = Math.floor(l / 2); i < l; i++)
            counter[str[i].charCodeAt(0) - 'a'.charCodeAt(0)]--;
        for (let i = 0; i < MAX; i++)
            if (counter[i] != 0)
                return true;

        return false;
    }

    // Driver function
    let str = "abcasdsabcae";
    if (Function(str))
        document.write("Yes, both halves"
            +" differ by at least one character");
    else
        document.write("No, both halves"
            +" do not differ at all");

    // This code is contributed by rag2127
</script>

Output

Yes, both halves differ by at least one character

Time Complexity: O(N), as we are using a loop to traverse N times. Where N is the length of the string.
Auxiliary Space: O(26), as we are using extra space for counter array.

Method 3: (No extra space)

• Input the string in form of character array
• Sort the two strings separately
• Traverse the two halves together, if these differ at any point, return true 
  to the calling function

Implementation:

C++

// C++ implementation to check if
// both halves of the string have
// at least one different character
#include <algorithm>
#include <cstring>
#include <iostream>
#include <string>
using namespace std;

// Function which break string into two halves
// Sorts the two halves separately
// Compares the two halves
// return true if any index has non-zero value
bool function(char str[])
{
    int l = strlen(str);

    // Declaration and initialization
    // of counter array
    sort(str, str + (l / 2));
    sort(str + (l / 2), str + l);
    for (int i = 0; i < l / 2; i++)
        if (str[i] != str[l / 2 + i])
            return true;
    return false;
}

// Driver function
int main()
{
    char str[] = "abcasdsabcae";
    if (function(str))
        cout << "Yes, both halves differ by"
             <<" at least one character";
    else
        cout << "No, both halves do"
             <<" not differ at all";
    return 0;
}

Java

// Java implementation to check if
// both halves of the string have
// at least one different character

import java.io.*;
import java.util.*;

class GFG {

// Function which break string into two halves
// Sorts the two halves separately
// Compares the two halves
// return true if any index has non-zero value
static Boolean function(char str[])
{
    int l = str.length;

    // Declaration and initialization
    // of counter array
    Arrays.sort(str, 0, (l / 2));
    Arrays.sort(str,(l / 2), l);
    for (int i = 0; i < l / 2; i++)
        if (str[i] != str[l / 2 + i])
            return true;
    return false;
}

    public static void main (String[] args) {
    char str[] = ("abcasdsabcae").toCharArray();
    if (function(str))
        System.out.println("Yes, both halves differ"
        + " by at least one character");
    else
        System.out.println("No, both halves do"
        + " not differ at all");
    }
}

// This code is contributed by Gitanjali.

Python3

# Python implementation to check if
# both halves of the string have
# at least one different character

# Function which break string into two halves
# Sorts the two halves separately
# Compares the two halves
# return true if any index has non-zero value
def function(st):
    st = list(st)
    l = len(st)

    # Declaration and initialization
    # of counter array
    st[:l//2] = sorted(st[:l//2])
    st[l//2:] = sorted(st[l//2:])
    for i in range(l//2):
        if (st[i] != st[l//2 + i]):
            return True
    return False

# Driver function
st = "abcasdsabcae"
if function(st): print("Yes, both halves differ ",
                       "by at least one character")
else: print("No, both halves do not differ at all")

# This code is contributed by Ansu Kumari

C#

// C# implementation to check if
// both halves of the string have
// at least one different character
using System;

class GFG
{

// Function which break string into two halves
// Sorts the two halves separately
// Compares the two halves
// return true if any index has non-zero value
static Boolean function(char []str)
{
    int l = str.Length;

    // Declaration and initialization
    // of counter array
    Array.Sort(str, 0, (l / 2));
    Array.Sort(str,(l / 2), l-(l/2));
    for (int i = 0; i < l / 2; i++)
        if (str[i] != str[l / 2 + i])
            return true;
    return false;
}

// Driver code
public static void Main (String[] args)
{
    char []str = ("abcasdsabcae").ToCharArray();
    if (function(str))
        Console.WriteLine("Yes, both halves differ"
        + " by at least one character");
    else
        Console.WriteLine("No, both halves do"
        + " not differ at all");
}
}

// This code contributed by Rajput-Ji

Javascript

<script>
// Javascript implementation to check if
// both halves of the string have
// at least one different character

    // Function which break string into two halves
    // Sorts the two halves separately
    // Compares the two halves
    // return true if any index has non-zero value
    function Function(str)
    {
        let l = str.length;

    // Declaration and initialization
    // of counter array
    str=(str.slice(0,Math.floor(l/2)).sort()).concat(str.slice(Math.floor(l/2),l).sort());
    for (let i = 0; i < Math.floor(l / 2); i++)
        if (str[i] != str[(Math.floor(l / 2) + i)])
            return true;
    return false;
    }

    let str="abcasdsabcae".split("");
    if (Function(str))
        document.write("Yes, both halves differ"
        + " by at least one character");
    else
        document.write("No, both halves do"
        + " not differ at all");

    // This code is contributed by avanitrachhadiya2155
</script>

Output

Yes, both halves differ by at least one character

Time Complexity: O(N*logN), as we are using sorting
Auxiliary Space: O(1), as we are not using any extra space.