不用topsort的，我也不知道为啥。
#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;
struct Node{
int fro, too;
}nd[2005];
struct Edge{
int too, nxt, val;
}edge[4000005];
int uu, vv, ww, n, hea[2005], cnt, dfn[2005], loo[2005], scc, bel[2005];
int sta[2005], din, ind;
bool ins[2005];
bool pd(int x, int y){
if(nd[x].fro<=nd[y].fro && nd[x].too>nd[y].fro) return true;
swap(x, y);
if(nd[x].fro<=nd[y].fro && nd[x].too>nd[y].fro) return true;
return false;
}
void add_edge(int fro, int too){
edge[++cnt].nxt = hea[fro];
edge[cnt].too = too;
hea[fro] = cnt;
}
void tarjan(int u){
dfn[u] = loo[u] = ++ind;
sta[++din] = u;
ins[u] = true;
for(int i=hea[u]; i; i=edge[i].nxt){
int t=edge[i].too;
if(!dfn[t]){
tarjan(t);
loo[u] = min(loo[u], loo[t]);
}
else if(ins[t]) loo[u] = min(loo[u], dfn[t]);
}
int j;
if(dfn[u]==loo[u]){
scc++;
do{
j = sta[din--];
ins[j] = false;
bel[j] = scc;
}while(dfn[j]!=loo[j]);
}
}
int main(){
cin>>n;
for(int i=0; i<n; i++){
scanf("%d:%d", &uu, &vv);
uu = uu * 60 + vv;
scanf("%d:%d", &vv, &ww);
vv = vv * 60 + ww;
scanf("%d", &ww);
nd[2*i].fro = uu, nd[2*i].too = uu + ww;
nd[2*i+1].fro = vv - ww, nd[2*i+1].too = vv;
}
for(int i=0; i<n+n; i++)
for(int j=i+1; j<n+n; j++)
if(pd(i, j)){
add_edge(i, j^1);
add_edge(j, i^1);
}
for(int i=0; i<n+n; i++)
if(!dfn[i])
tarjan(i);
for(int i=0; i<n+n; i+=2)
if(bel[i]==bel[i^1]){//说明以前有要求既不能选i又不能选i^1
printf("NO
");
return 0;
}
printf("YES
");
for(int i=0; i<n+n; i+=2){
int id=bel[i]<bel[i^1]?i:i+1;//为什么要这样做？id小说明先求出来，在图里是靠近下游的，影响小
printf("%02d:%02d %02d:%02d
", nd[id].fro/60, nd[id].fro%60, nd[id].too/60, nd[id].too%60);
}
return 0;
}