Check Permutation

 

For a given two strings, 'str1' and 'str2', check whether they are a permutation of each other or not.

Permutations of each other

Two strings are said to be a permutation of each other when either of the string's characters can be rearranged so that it becomes identical to the other one.

Example: 
str1= "sinrtg" 
str2 = "string"

The character of the first string(str1) can be rearranged to form str2 and hence we can say that the given strings are a permutation of each other.

Input Format:

The first line of input contains a string without any leading and trailing spaces, representing the first string 'str1'.

The second line of input contains a string without any leading and trailing spaces, representing the second string 'str2'.

Note:

All the characters in the input strings would be in lower case.

Output Format:

The only line of output prints either 'true' or 'false', denoting whether the two strings are a permutation of each other or not.

You are not required to print anything. It has already been taken care of. Just implement the function. 

Constraints:

0 <= N <= 10^6
Where N is the length of the input string.

Time Limit: 1 second

Sample Input 1:

abcde
baedc

Sample Output 1:

true

Sample Input 2:

abc
cbd

Sample Output 2:

false

#include <iostream>

#include <cstring>

using namespace std;

#include "solution.h"

#include <bits/stdc++.h> 

bool isPermutation(char str1[], char str2[]){ 

    // Create 2 count arrays and initialize  

    // all values as 0 

    int count1[256] = {0}; 

    int count2[256] = {0}; 

    int i; 

  

    // For each character in input strings,  

    // increment count in the corresponding  

    // count array 

    for (i = 0; str1[i] && str2[i];  i++) 

    { 

        count1[str1[i]]++; 

        count2[str2[i]]++; 

    } 

  

    // If both strings are of different length.  

    // Removing this condition will make the 

    // program fail for strings like "aaca" 

    // and "aca" 

    if (str1[i] || str2[i]) 

      return false; 

  

    // Compare count arrays 

    for (i = 0; i < 256; i++) 

        if (count1[i] != count2[i]) 

            return false; 

  

    return true; 

} 

int main() {

    int size = 1e6;

    char str1[size];

    char str2[size];

    cin >> str1 >> str2;

    cout << (isPermutation(str1, str2) ? "true" : "false");

}

////////////////////////////////////////////////////////////////////////

bool isPermutation(char input1[], char input2[]) {

    // Write your code here

    int freq[256]={0};

    

    if(strlen(input1)!=strlen(input2)){

        return false;

    }

    else{

    for(int i=0;i<strlen(input1);i++){

        int ascii=input1[i];

        freq[ascii]++;

    }

    

    for(int i=0;i<strlen(input2);i++){

        int ascii=input2[i];

        freq[ascii]--;

    }

    

    for(int i=0;i<256;i++){

        if(freq[i]!=0){

            return false;

            

        }

        

    }

    return true;

    }

}