Submission #974407

#	Time	Username	Problem	Language	Result	Execution time	Memory
974407		sleepntsheep	Village (BOI20_village)	C11	100 / 100	42 ms	12112 KiB

Village

#include<stdio.h>

#define N 100000
#define M (2*N)

int ded[N],n, p1[N],head[N], nxt[M], vv[M], eo = 1, tin[N], timer, aux[N],sz[N],qu[N],qh,qt,deg[N];
void link(int u,int v)
{
    int i = eo++;
    nxt[i]=head[u],vv[i]=v,head[u]=i;
    ++deg[v];
}

long long max, min;
void dfs(int u,int p)
{
    sz[u]=1;
    aux[tin[u] = timer++] = u;
    for (int j =head[u];j;j=nxt[j])if(p!=vv[j]){
        dfs(vv[j],u);
        max+=sz[vv[j]]<(n-sz[vv[j]])?sz[vv[j]]:n-sz[vv[j]];
        sz[u]+=sz[vv[j]];
    }
}

int main()
{
    scanf("%d",&n);
    for(int i=1,u,v;i<n;++i)scanf("%d%d",&u,&v),link(--u,--v),link(v,u);
    dfs(0,0);
    for(int i=0;i<n;++i)p1[i]=i;

    for(int i=0;i<n;++i)if(deg[i]==1)qu[qh++]=i;
    while(qh-qt)
    {
        int temp,u=qu[qt++],f=0;
        for(int j=head[u];j;j=nxt[j])
        {
            int v=vv[j];
            if(!ded[v]){
                if(--deg[v]==1)
                    qu[qh++]=v;
                f=1;
                if(p1[u]==u)
                {
                    min+=2;
                    temp=p1[u],p1[u]=p1[v],p1[v]=temp;
                }
                break;
            }
        }
        if(!f&&p1[u]==u)
        {
            int v=vv[head[u]];
            temp=p1[u],p1[u]=p1[v],p1[v]=temp;
            min+=2;
        }
        ded[u]=1;
    }

    printf("%lld %lld\n",min,max<<1);
    for(int i=0;i<n;++i)
        printf("%d ",1+p1[i]);
    putchar(10);
    for(int i=0;i<n;++i)
        printf("%d ",1+aux[(tin[i]+n/2)%n]);
}

Compilation message (stderr)

Village.c: In function 'main':
Village.c:28:5: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   28 |     scanf("%d",&n);
      |     ^~~~~~~~~~~~~~
Village.c:29:29: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   29 |     for(int i=1,u,v;i<n;++i)scanf("%d%d",&u,&v),link(--u,--v),link(v,u);
      |                             ^~~~~~~~~~~~~~~~~~~

• Subtask 1: 12 / 12
• Subtask 2: 38 / 38
• Subtask 3: 50 / 50