Luogu1137 旅行計劃(拓撲排序)
阿新 • • 發佈:2018-08-31
ret spa set () max printf urn name double
題目傳送門
拓撲排序板子題,模擬即可。
代碼
#include<cstdio> #include<iostream> #include<cmath> #include<cstring> #include<algorithm> #include<set> #include<map> using namespace std; #define rep(i,l,r) for(register int i=(l);i<=(r);++i) #define repdo(i,l,r) for(register int i=(l);i>=(r);--i) #define il inline typedef double db; typedef long long ll; //--------------------------------------- const int nsz=100050,msz=200050; int n,m; struct te{int t,pr;}edge[msz]; int hd[nsz],pe=1,in[nsz]; void adde(int f,int t){edge[++pe]=(te){t,hd[f]};hd[f]=pe;} int que[nsz],qh=1,qt=0; int ts[nsz],pt=0; bool topsort(){ rep(i,1,n)if(in[i]==0)que[++qt]=i,ts[++pt]=i; while(qh<=qt){ int u=que[qh++]; for(int i=hd[u],v=edge[i].t;i;i=edge[i].pr,v=edge[i].t){ --in[v]; if(in[v]==0)ts[++pt]=v,que[++qt]=v; } } return pt==n; } int dp[nsz]; void getdp(){ rep(i,1,n)dp[i]=1; rep(p,1,pt){ for(int i=hd[ts[p]],v=edge[i].t;i;i=edge[i].pr,v=edge[i].t){ dp[v]=max(dp[v],dp[ts[p]]+1); } } } int main(){ ios::sync_with_stdio(0),cin.tie(0); cin>>n>>m; int a,b; rep(i,1,m)cin>>a>>b,adde(a,b),++in[b]; topsort(); //rep(i,1,pt)printf("%d ",ts[i]); getdp(); rep(i,1,n)cout<<dp[i]<<'\n'; return 0; } // freopen(".in","r",stdin); // freopen(".out","w",stdout);
Luogu1137 旅行計劃(拓撲排序)