水题，P1789 【Mc生存】插火把 （暴力即可）

#include<cstdio>
#define maxn int(1e4)
bool dp[maxn][maxn];
int n;

void f1(int x, int y)
{
    dp[x][y] = 1;
    int i = x + 1, j = y;
    int k = 0;
    while (1)
    {
        ++k;
        if (i > 0 && i <= n&&j > 0 && j <= n)dp[i][j] = 1;
        if (k == 1 || k == 4)++j;
        else --j;
        if (k == 1 || k == 2)--i;
        else ++i;
        if (i == x + 1 && j == y)break;
    }
    i = x + 2; j = y; k = 0;
    while (1)
    {
        ++k;
        if (i > 0 && i <= n&&j > 0 && j <= n)dp[i][j] = 1;
        if (k ==1||k==2||k==7||k==8)++j;
        else --j;
        if (k == 5 || k == 6 || k == 7 || k == 8)++i;
        else --i;
        if (i == x + 2 && j == y)break;
    }
}

void f2(int x, int y)
{
    for (int i = x - 2; i <= x + 2;++i)
    for (int j = y - 2; j <= y + 2;++j)
    if (i > 0 && i <= n&&j > 0 && j <= n)dp[i][j] = 1;
}

int main()
{
    int k, t;
    scanf("%d%d%d", &n, &k, &t);
    for (int i = 0; i < k; ++i)
    {
        int x, y;
        scanf("%d%d", &x, &y);
        f1(y, x);
    }
    for (int i = 0; i < t; ++i)
    {
        int x, y;
        scanf("%d%d", &x, &y);
        f2(y, x);
    }
    int ans = 0;

//    for (int i = 1; i <= n; ++i)
//    {
//        for (int j = 1; j <= n; ++j)
//        if (dp[i][j])printf("*");
//        else printf(".");
//        printf("\n");
//    }
    for (int i = 1; i <= n;++i)
    for (int j = 1; j <= n;++j)
    if (!dp[i][j])++ans;
    printf("%d\n", ans);
}