[Noi2010]Plane 航空管制 贪心

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
#define N 2100
#define M 11000
int t[N];
int n,m;
int dp[N];
int ru[N],op[N];
int e[N],ne[M],v[M];
int nn,been1[N],been2[N];
int q[N],he,bo;
struct P{
   int x,y;
   P(int a=0,int b=0){
      x=a,y=b;
    }
   bool operator<(P a)const{
        return y<a.y;
    }
}rc[N];
void add(int x,int y){
    ne[++nn]=e[x],e[x]=nn,v[nn]=y;
}
int f[N];
int tot;
int get(int x){
   return f[x]==x?x:f[x]=get(f[x]);
}
int ans[N];
int solv(int x){
    memset(been1,0,sizeof(been1));
    memset(been2,0,sizeof(been2));
    for(int i=0;i<=n;i++)f[i]=i;
    been1[x]=1;
    int y,a1=0,a2=0;
    for(int j=1;j<=n;j++){
          for(int i=e[y=op[j]];i;i=ne[i]){
            if(been1[y])been1[v[i]]=1;
        }
        if(been1[y])a1++;
    }
    been2[x]=1;
    for(int j=n;j>=1;j--){
           for(int i=e[y=op[j]];i;i=ne[i]){
           if(been2[v[i]])been2[y]=1;
        }
        if(been2[y])a2++;
    }
    for(int i=1;i<=n;i++){
           if(!been1[i]&&!been2[i]){
           y=get(dp[i]);
           f[y]=get(y-1);
        }
    }
    int now=n+1;
    for(int i=1;i<=a2;i++){
        now=get(now-1);
    }
    return now;
}
int main(){
    scanf("%d%d",&n,&m);
    for(int i=1;i<=n;i++)scanf("%d",&t[i]),t[i]=min(t[i],n),dp[i]=t[i];
    for(int i=1;i<=m;i++){
        int a,b;
        scanf("%d%d",&a,&b);
        add(b,a);
        ru[a]++;
    }
    he=0;
    bo=1;
    int x;
    for(int i=1;i<=n;i++)if(!ru[i])q[++he]=i;
    while(he>=bo){
       x=q[bo++];
       rc[x]=P(x,dp[x]);
       op[++tot]=x;
       for(int i=e[x];i;i=ne[i]){
           ru[v[i]]--;
           dp[v[i]]=min(dp[v[i]],dp[x]-1);
           if(!ru[v[i]])q[++he]=v[i];
        }
    }
    sort(rc+1,rc+n+1);
    for(int i=1;i<=n;i++)printf("%d ",rc[i].x);
    printf("\n");
    for(int i=1;i<=n;i++)printf("%d ",solv(i));
}

[Noi2010]Plane 航空管制 贪心