洛谷：P1789 【Mc生存】插火把

 代码：

#include<stdio.h>

struct huobaye{
    int x;
    int y;
};

struct stoneye{
    int x;
    int y;
};

int abs(int n)
{
    int flag;
    if(n>=0)
    flag=n;
    else
        flag = -1*n;
    return flag;
}

int main()
{

    int i,j,n,m,k;
    scanf("%d%d%d",&n,&m,&k);
    //25 5
    struct huobaye huoba[25];
    struct stoneye stone[5];
    //int a,b;
    for(i=1;i<=m;i++)
    {
        scanf("%d%d",&huoba[i].x,&huoba[i].y);
    }
    if(k>=1)
    {
        for(i=1;i<=k;i++)
        {
            scanf("%d%d",&stone[i].x,&stone[i].y);
        }
    }
    int location[101][101]={0};
    int dx[] = {-2,-1,1,2};
    int dy[] = {2,1,-1,-2};
    int dz[]={-1,1,1,1,-1,-1,1,-1};
    int djs;
    int q,p;
    for(i=1;i<=m;i++)
    {
        q = huoba[i].x;
        p = huoba[i].y;
        djs=1;
        while(djs)
        {
            for(j=0;j<4;j++)
            {
                if(p+dx[j]>0 && p+dx[j]<=n)
                {
                    location[q][p+dx[j]]=1;
                }
                if(q+dy[j]>0 && q+dy[j]<=n)
                {
                    location[q+dy[j]][p]=1;
                }
            }
            for(j=0;j<8;)
            {
                if((q+dz[j]>0&&q+dz[j]<=n)&&(p+dz[j+1]>0&&p+dz[j+1]<=n))
                    location[q+dz[j]][p+dz[j+1]]=1;

                j+=2;
            }
            djs--;
        }
        location[q][p]=1;
    }
    int s,t;
    if(k>=1)
    {
        for(i=1;i<=k;i++)
        {
            q = stone[i].x;
            p = stone[i].y;
            for(s=1;s<=n;s++)
                for(t=1;t<=n;t++)
            {
                 if(abs(s-q)<=2&&abs(t-p)<=2)
                    location[s][t]=1;
            }
            location[q][p]=1;
        }
    }
    int count=0;
    for(i=1;i<=n;i++)
        for(j=1;j<=n;j++)
    {
        if(location[i][j]==0)
            count++;
    }
    printf("%d",count);
    return 0;
}

　　同样使用了位置数组