InterviewBit/maxspprod.cpp at master · vedavikas06/InterviewBit · GitHub

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int Solution::maxSpecialProduct(vector<int> &A) {

    int n = A.size();


    vector<long long> l(n,0),r(n,0);
    stack<long long> s;
    for(long long i= 0;i<n;i++){

        if(s.empty()){
            s.push(i);
        }else{

            while(!s.empty() && A[s.top()] <= A[i]){
                s.pop();
            }

            if(!s.empty()){
                l[i] = s.top();

            }

            s.push(i);


        }
    }
    while(!s.empty()){
    s.pop();
    }

     for(long long i= n-1;i>=0;i--){

        if(s.empty()){
            s.push(i);
        }else{

            while(!s.empty() && A[s.top()] <= A[i]){
                s.pop();
            }

            if(!s.empty()){
                r[i] = s.top();

            }
            s.push(i);

        }

    }

    long long maxx = 0;
    long long mod = 1000000007;
    for(int i =0;i<n;i++){
        //cout << l[i] << " " << r[i] << endl;
        long long val = (l[i]*r[i]*1LL);
        maxx= max(val,maxx);


    }


    return maxx%mod;


}