Задача 4

#include <iostream>

using namespace std;

const int N = 1e3+5;

int n, m, ans, ks, kb, xx, yy, x, y;
bool used[N][N];
int M[N][N];

void dfs(int x, int y){
    if(x<0 || y<0 ||x>=n || y>=m || M[x][y] ==2|| used[x][y]){ return; }
    used[x][y] = 1;
    if(M[x][y]==1) --ans;
    for(int i = -1; i < 2; ++i){
        for(int j = -1; j < 2; ++j){
            if(i && j) continue;
            dfs(x+i,y+j);
        }
    }
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    cin >> n >> m >> ks >> kb >> xx >> yy;
    ans = kb;
    for(int i = 0; i < ks; ++i){
        cin >> x >> y;
        M[x][y] = 2;
    }
    for(int i = 0; i < kb; ++i){
        cin >> x >> y;
        M[x][y] = 1;
    }
    dfs(yy,xx);
    cout << ans;

    return 0;
}