板子:
#include <map>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#define sg string
#define ll long long
#define rep(i,x,y) for(ll i=(x);i<=(y);i++)
#define repd(i,x,y) for(ll i=(x);i>=(y);i--)
using namespace std;
const ll N=2e5+5;
ll n,m,cc;
ll cnt,to[N<<1],nxt[N<<1],head[N];
ll tot,num,top,dfn[N],low[N],bel[N],vis[N],stack[N];
map<string,ll>mp;
struct node {
ll x,y;
}cp[N];
void ins(ll x,ll y) {
to[++cnt]=y;nxt[cnt]=head[x];head[x]=cnt;
}
void tarjan(ll x) {
dfn[x]=low[x]=++num;vis[x]=1;stack[++top]=x;
for(ll i=head[x];i;i=nxt[i]) {
ll y=to[i];
if(!dfn[y]) tarjan(y),low[x]=min(low[x],low[y]);
else if(vis[y]) low[x]=min(low[x],dfn[y]);
}
if(dfn[x]==low[x]) {
vis[x]=0;bel[x]=++tot;
while(stack[top]!=x) {
bel[stack[top]]=tot;
vis[stack[top--]]=0;
}top--;
}
}
int main() {
cin>>n;
rep(i,1,n) {
sg a,b;ll x,y;
cin>>a>>b;
if(!mp[a]) x=mp[a]=++cc;
else x=mp[a];
if(!mp[b]) y=mp[b]=++cc;
else y=mp[b];
ins(y,x);cp[i].x=x,cp[i].y=y;
}
cin>>m;
rep(i,1,m) {
sg a,b;ll x,y;
cin>>a>>b;
if(!mp[a]) x=mp[a]=++cc;
else x=mp[a];
if(!mp[b]) y=mp[b]=++cc;
else y=mp[b];
ins(x,y);
}
rep(i,1,cc) if(!dfn[i]) tarjan(i);
rep(i,1,n) {
if(bel[cp[i].x]==bel[cp[i].y]) puts("Unsafe");
else puts("Safe");
}
return 0;
}