addsqure.cpp

#include <bits/stdc++.h>
#include<algorithm>
using namespace std;

// Function to count all the possible
// squares with given lines parallel
// to both the X and Y axis
int numberOfSquares(int X[], int Y[],
					int N, int M)
{
	// Stores the count of all possible
	// distances in X[] & Y[] respectively
	unordered_map<int, int> m1, m2;
	int i, j, ans = 0;

	// Find distance between all
	// pairs in the array X[]
	for (i = 0; i < N; i++) {
		for (j = i + 1; j < N; j++) {

			int dist = abs(X[i] - X[j]);

			// Add the count to m1
			m1[dist]++;
		}
	}

	// Find distance between all
	// pairs in the array Y[]
	for (i = 0; i < M; i++) {
		for (j = i + 1; j < M; j++) {

			int dist = abs(Y[i] - Y[j]);

			// Add the count to m2
			m2[dist]++;
		}
	}

	// Find sum of m1[i] * m2[i]
	// for same distance
	for (auto i = m1.begin();
		i != m1.end(); i++) {

		// Find current count in m2
		if (m2.find(i->first)
			!= m2.end()) {

			// Add to the total count
			ans += 1;
		}
	}

	// Return the final count
	return ans;
}

bool found(int Y[],int i,int m){
    int l=0,u=m-1,mid;
    while(l<=u){
        mid=(l+u)/2;
        if(Y[mid]==i)return true;
        else if(Y[mid]<i)l=mid+1;
        else u=mid-1;
    }return false;
}

// Driver Code
int main()
{   	ios_base::sync_with_stdio(false);
cin.tie(NULL);
	int w,h,n,m;
	cin>>w>>h>>n>>m;
	vector<int> A;
	int X[n];
	for(int i=0;i<n;i++)cin>>X[i];
	int Y[m+1];
	for(int j=0;j<m;j++)cin>>Y[j];
    sort(X,X+n);sort(Y,Y+m);
    int x=X[n-1]-X[0];
    x+=Y[m-1];
    A.push_back(numberOfSquares(X,Y,n,m+1));
    for(int i=1;i<=h;i++){
        if(!found(Y,i,m))
        {   
            Y[m]=i;
            A.push_back(numberOfSquares(X, Y, n, m+1));
        }
    }cout<<*max_element(A.begin(), A.end());
	return 0;
}