[P2119]魔法阵 (模拟？搜索？)

Posted 2021-01-18 fsy2017

很玄学

我暴力都没做出来

#include <cstdio>
int n,m,x[40001],vis[15001],a[15001],b[15001],c[15001],d[15001];
int main() {
    //freopen("magic.in","r",stdin);
    //freopen("magic.out","w",stdout);
    scanf("%d%d",&n,&m);
    for (int i = 1;i <= m;i++) {
        scanf("%d",&x[i]);
        vis[x[i]]++;
    }
    for (int i = 1;i <= n/9;i++) {
        int sum = 0;
        for (int j = i*9+2;j <= n;j++) {
            sum += vis[j-(9*i+1)]*vis[j-(9*i+1)+2*i];
            d[j] += sum*vis[j-i];
            c[j-i]+=sum*vis[j];
        }
        sum = 0;
        for (int j = n-(9*i+1);j >= 1;j--) {
            sum += vis[j+(9*i+1)]*vis[j+(9*i+1)-i];
            a[j] += sum*vis[j+2*i];
            b[j+2*i] += sum*vis[j];

        }
    }
    for (int i = 1;i <= m;i++) printf("%d %d %d %d
",a[x[i]],b[x[i]],c[x[i]],d[x[i]]);
    return 0;
}