Day-044.cpp

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

// program for finding permutations of 1 string in other string
class Solution {
    bool checkEqual(int a[26],int b[26]){
        for(int i = 0;i<26;i++){
            if(a[i] != b[i])
                return 0;
        }
        return 1;
    }
public:
    bool checkInclusion(string s1, string s2) {
        // character count array
        int count1[26] = {0};
        for(int i=0; s1[i] != '\0';i++){
            int index = s1[i] - 'a';
            count1[index]++;
        }
        // traverse s2 string in window of size s1 length and compare
        int i=0;
        int windowSize = s1.length();
        int count2[26] = {0};
        // running for first window
        while(i < windowSize && s2[i]!='\0'){
            int index = s2[i] - 'a';
            count2[index]++;
            i++;
        }
        if(checkEqual(count1,count2))
            return 1;
        
        // aage window process karo
        while(i<s2.length()){
            char newChar = s2[i];
            int index = newChar - 'a';
            count2[index]++;
            
            char oldChar = s2[i-windowSize];
            index = oldChar - 'a';
            count2[index]--;
            i++;
            if(checkEqual(count1,count2))
            return 1;
        }
        return 0;
    }
};
int main (){
    string s1 = "ab";
    string s2 = "eidbaooo";
    Solution obj1;
    int i = obj1.checkInclusion(s1, s2);
    cout << "function is present " << i << endl;
return 0;
}