PermutationInString.cpp

#include <iostream>
#include <string>
using namespace std;

bool isFreqSame(int freq1[], int freq2[])
{
    for (int i = 0; i < 26; i++)
    {
        if (freq1[i] != freq2[i])
        {
            return false;
        }
    }

    return true;
}

bool checkInclusion(string s1, string s2)
{
    int freq[26] = {0};

    for (int i = 0; i < s1.length(); i++)
    {
        freq[s1[i] - 'a']++;
    }

    int windSize = s1.length();

    for (int i = 0; i < s2.length(); i++)
    {
        int windIdx = 0, idx = i;
        int windfreq[26] = {0};

        while (windIdx < windSize && idx < s2.length())
        {
            windfreq[s2[idx] - 'a']++;
            windIdx++;
            idx++;
        }

        if (isFreqSame(freq, windfreq))
        {
            return true;
        }
    }

    return false;
}

int main()
{

    string s1 = "ab";
    string s2 = "eidbaooo";

    cout << checkInclusion(s1, s2) << endl;

    return 0;
}