hdu5195 DZY Loves Topological Sorting 线段树+拓扑排序

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<queue>
#include<algorithm>
#include<vector>
using namespace std;
const int N = 400000 +10;
const int inf = 1e8+10;
vector<int> G
;
int d
;
int tops
,minv
;
int n,m,k,u,v,res,num;
int query(int o,int L,int R)
{
    int M = L + (R-L)/2;
    if(L==R) return L;
    if(minv[o*2+1]<=res) return query(o*2+1,M+1,R);
    return query(o*2,L,M);
}

int p,fl
;
void update(int o,int L ,int R)
{
    int M = L + (R-L)/2;
    if(L==R){
        minv[o] = v;
    }
    else{
        if(p <= M) update(o*2,L,M);
        else update(o*2+1,M+1,R);
        minv[o] = min(minv[o*2],minv[o*2+1]);
    }
}
void change(int pl , int x)
{
     p =pl;
     v = x;
     update(1,1,n);
}

void build()
{
    for(int i=1;i<=n;i++){
        p = i;
        v = d[i];
        update(1,1,n);
    }
}

void solve()
{
    for(int i=1;i<=n;i++){
        int id = query(1,1,n);
        int tmp;
        res -= d[id];
        fl[id]=1;
        tops[++num] = id;
        change(id,inf);
        int size = G[id].size();
        for(int j=0;j<size;j++) {
            tmp = G[id][j];
            if(fl[tmp]) continue;
            d[tmp]--;
            change(tmp,d[tmp]);
        }
    }
}

int main(){
    while(scanf("%d%d%d",&n,&m,&k)!=EOF){
        res = k; num = 0;
        memset(d,0,sizeof(d));
        memset(fl,0,sizeof(fl));
        for(int i=1;i<=n;i++) G[i].clear();
        for(int i=1;i<=m;i++){
            scanf("%d%d",&u,&v);
            G[u].push_back(v);
            d[v]++;
        }
        build();
        solve();
        for(int i=1;i<=num;i++){
            printf("%d",tops[i]);
            if(i==num) printf("\n");
            else printf(" ");
        }
    }
    return 0;
}