QOJ.ac
QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#414770 | #6559. A Tree and Two Edges | karuna# | WA | 25ms | 7396kb | C++20 | 2.1kb | 2024-05-19 17:11:25 | 2024-05-19 17:11:26 |
Judging History
answer
#include <bits/stdc++.h>
#define ff first
#define ss second
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int MAXN = 5e4;
int N, Q;
vector<int> adj[MAXN+10];
vector<vector<int>> V;
vector<pii> E;
int vis[MAXN+10], par[MAXN+10];
void dfs(int now, int bef)
{
vis[now]=1;
par[now]=bef;
for(int nxt : adj[now])
{
if(nxt==bef) continue;
if(vis[nxt]==0) dfs(nxt, now);
else if(vis[nxt]==1)
{
vector<int> VV;
for(int i=now; i!=nxt; i=par[i]) VV.push_back(i);
VV.push_back(nxt);
V.push_back(VV);
}
}
vis[now]=2;
}
bool P[MAXN+10];
int P2[MAXN+10];
void chk(int u, int v)
{
if(u>v) swap(u, v);
P[lower_bound(E.begin(), E.end(), pii(u, v))-E.begin()]=1;
}
struct UF
{
int par[MAXN+10];
void init()
{
for(int i=1; i<=N; i++) par[i]=i;
}
int Find(int x)
{
if(x==par[x]) return x;
return par[x]=Find(par[x]);
}
void Union(int x, int y)
{
x=Find(x);
y=Find(y);
par[x]=y;
}
}uf;
int main() {
cin.tie(0); ios_base::sync_with_stdio(0);
scanf("%d%d", &N, &Q);
for(int i=1; i<=N+1; i++)
{
int u, v;
scanf("%d%d", &u, &v);
if(u>v) swap(u, v);
E.push_back({u, v});
adj[u].push_back(v);
adj[v].push_back(u);
}
uf.init();
sort(E.begin(), E.end());
dfs(1, 1);
//assert(V.size()==2);
for(int i=0; i+1<V[0].size(); i++) chk(V[0][i], V[0][i+1]);
chk(V[0][V[0].size()-1], V[0][0]);
for(int i=0; i+1<V[1].size(); i++) chk(V[1][i], V[1][i+1]);
chk(V[1][V[1].size()-1], V[1][0]);
for(int i=0; i<E.size(); i++)
{
if(P[i]) continue;
uf.Union(E[i].first, E[i].second);
}
for(auto jt : V[0]) P2[uf.Find(jt)]|=1;
for(auto jt : V[1]) P2[uf.Find(jt)]|=2;
int cnt=0;
for(int i=1; i<=N; i++) if(P2[i]==3) cnt++;
while(Q--)
{
int u, v;
scanf("%d%d", &u, &v);
if(uf.Find(u)==uf.Find(v)) printf("1\n");
else if(P2[uf.Find(u)]==3 || P2[uf.Find(v)]==3)
{
if(cnt==1) printf("2\n");
else printf("3\n");
}
else if(P2[uf.Find(u)]==P2[uf.Find(v)])
{
if(cnt==1) printf("2\n");
else printf("3\n");
}
else printf("4\n");
}
}
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 1ms
memory: 3744kb
input:
4 6 1 2 1 3 1 4 2 3 2 4 1 2 1 3 1 4 2 3 2 4 3 4
output:
3 3 3 3 3 4
result:
ok 6 lines
Test #2:
score: 0
Accepted
time: 1ms
memory: 3804kb
input:
6 4 1 2 1 3 1 6 2 3 3 4 3 5 4 5 1 2 1 3 1 4 1 6
output:
2 2 4 1
result:
ok 4 lines
Test #3:
score: -100
Wrong Answer
time: 25ms
memory: 7396kb
input:
50000 50000 11561 23122 14261 28523 24407 48814 17947 35894 14803 29607 19557 39115 12415 24830 9583 19167 18397 36794 439 878 18040 36080 17150 34300 7922 15845 18938 37877 18625 37250 6459 12919 9818 19636 3579 7158 21323 42646 23882 47764 13603 27207 8353 16707 15907 31814 20935 41871 11686 23372...
output:
3 3 3 3 3 3 1 3 3 1 3 3 3 3 3 3 1 3 3 3 3 3 3 3 3 3 3 3 3 3 1 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 1 3 1 1 3 3 3 3 3 3 1 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 1 3 3 3 3 3 3 3 3 3 3 1 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 1 3 3 3 3 3 3 3 ...
result:
wrong answer 1st lines differ - expected: '4', found: '3'