Interleaving String.cpp

class Solution {
public:

    unordered_map<string,bool> mp;

    bool check(string s1, string s2, string s3, int len1, int len2, int len3, int p1, int p2, int p3){

        if(p3 == len3){
            return (p1 == len1 && p2 == len2)?true:false;
        }

        string key = to_string(p1)+"*"+to_string(p2)+"*"+to_string(p3);


        if(mp.find(key) != mp.end()){
            return mp[key];
        }

        // cases for calcualting the Keys

        if(p1 == len1){
            return mp[key] = s2[p2] == s3[p3]?check(s1,s2,s3,len1,len2,len3,p1,p2+1,p3+1):false;
        }

        if(p2 == len2){
            return mp[key] = s1[p1] == s3[p3]?check(s1,s2,s3,len1,len2,len3,p1+1,p2,p3+1):false;
        }

        bool one = false,two = false;

        if(s1[p1] == s3[p3]){
            one = check(s1,s2,s3,len1,len2,len3,p1+1,p2,p3+1);
        } 
        if(s2[p2] == s3[p3]){
            two = check(s1,s2,s3,len1,len2,len3,p1,p2+1,p3+1);
        }

        return mp[key] = (one || two);

    }


    bool isInterleave(string s1, string s2, string s3) {

        int n1 = s1.length(),n2 = s2.length(), n3 = s3.length();

        if(n1 + n2 != n3){
            return false;
        }

        return check(s1,s2,s3,n1,n2,n3,0,0,0);
    }
};