#include <bits/stdc++.h>
using namespace std;
// macros
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef pair<ll, ll> lll;
typedef tuple<int, int, int> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<iii> viii;
typedef vector<ll> vll;
typedef vector<lll> vlll;
#define REP(a,b,c) for(int a=int(b); a<int(c); a++)
#define RE(a,c) REP(a,0,c)
#define RE1(a,c) REP(a,1,c+1)
#define REI(a,b,c) REP(a,b,c+1)
#define REV(a,b,c) for(int a=int(c-1); a>=int(b); a--)
#define FOR(a,b) for(auto& a : b)
#define all(a) a.begin(), a.end()
#define INF 1e9
#define EPS 1e-9
#define pb push_back
#define popb pop_back
#define fi first
#define se second
#define sz size()
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
// input
template<class T> void IN(T& x) {cin >> x;}
template<class H, class... T> void IN(H& h, T&... t) {IN(h); IN(t...); }
// output
template<class T1, class T2> void OUT(const pair<T1,T2>& x);
template<class T> void OUT(const T& x) {cout << x;}
template<class H, class... T> void OUT(const H& h, const T&... t) {OUT(h); OUT(t...); }
template<class T1, class T2> void OUT(const pair<T1,T2>& x) {OUT(x.fi,' ',x.se);}
template<class... T> void OUTL(const T&... t) {OUT(t..., "\n"); }
template<class H> void OUTLS(const H& h) {OUTL(h); }
template<class H, class... T> void OUTLS(const H& h, const T&... t) {OUT(h,' '); OUTLS(t...); }
//===================//
// Added libraries //
//===================//
//===================//
//end added libraries//
//===================//
void program();
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
program();
}
//===================//
// begin program //
//===================//
const int MX = 5e5;
int n, m;
int a[MX], b[MX];
set<int> adj[MX];
bitset<MX> used;
int p[MX], r[MX];
stack<iii> stck;
void buildDSU(int dsuSize) {
RE(i,dsuSize) p[i]=i, r[i]=0;
while(!stck.empty()) stck.pop();
}
int getSet(int i) {return i==p[i]?i:getSet(p[i]);}
bool isSameSet(int i, int j) {return getSet(i)==getSet(j);}
void unionSet(int i, int j) {
i=getSet(i), j=getSet(j);
if(r[i] > r[j]) {
stck.push({j,i,r[i]});
p[j] = i;
} else {
p[i] = j;
stck.push({i,j,r[j]});
if(r[i] == r[j] && i != j) r[j]++;
}
}
void unionUndo() {
int i, j, rj;
tie(i,j,rj) = stck.top(); stck.pop();
r[j] = rj;
p[i] = i;
}
vi ans;
int par[MX];
bitset<MX> visited;
void findShortestPath(int x, int y) {
visited.reset(); visited[x] = 1;
queue<int> q; q.push(x);
while(!q.empty()) {
int u = q.front(); q.pop();
FOR(v,adj[u]) if(!visited[v]) {
visited[v] = 1;
q.push(v);
par[v] = u;
}
}
while(y != x) {
ans.pb(y);
y = par[y];
}
ans.pb(x);
}
void program() {
IN(n,m);
RE(i,m) {
int u, v; IN(u, v);
adj[u].insert(v);
adj[v].insert(u);
a[i] = u; b[i] = v;
}
RE1(u,n) {
// create initial dsu
used.reset();
buildDSU(n+1);
used[u] = 1;
FOR(v,adj[u]) used[v] = 1;
RE(i,m) {
int u=a[i], v=b[i];
if(used[u] || used[v]) continue;
unionSet(u, v);
}
FOR(x,adj[u]) {
FOR(y,adj[u]) {
if(adj[x].count(y) || x == y) continue;
// update dsu
used[x] = 0;
used[y] = 0;
FOR(v,adj[x]) if(!used[v]) unionSet(x,v);
FOR(v,adj[y]) if(!used[v]) unionSet(y,v);
if(isSameSet(x,y)) {
// found answer
RE1(i,n) adj[i].clear();
RE(i,m) {
int u=a[i], v=b[i];
if(used[u] || used[v]) continue;
adj[u].insert(v);
adj[v].insert(u);
}
ans.pb(u);
findShortestPath(x,y);
RE(i,ans.sz) OUT(i==0?"":" ", ans[i]); OUTL();
return;
}
// reset dsu
FOR(v,adj[x]) if(!used[v]) unionUndo();
FOR(v,adj[y]) if(!used[v]) unionUndo();
used[x] = 1;
used[y] = 1;
}
}
}
OUTL("no");
}
Compilation message
indcyc.cpp: In function 'void program()':
indcyc.cpp:15:20: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
15 | #define REP(a,b,c) for(int a=int(b); a<int(c); a++)
| ^~~
indcyc.cpp:16:17: note: in expansion of macro 'REP'
16 | #define RE(a,c) REP(a,0,c)
| ^~~
indcyc.cpp:160:21: note: in expansion of macro 'RE'
160 | RE(i,ans.sz) OUT(i==0?"":" ", ans[i]); OUTL();
| ^~
indcyc.cpp:160:60: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
160 | RE(i,ans.sz) OUT(i==0?"":" ", ans[i]); OUTL();
| ^~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
16 ms |
23936 KB |
Output is correct |
| 2 |
Correct |
16 ms |
23936 KB |
Output is correct |
| 3 |
Correct |
16 ms |
23936 KB |
Output is correct |
| 4 |
Correct |
18 ms |
23936 KB |
Output is correct |
| 5 |
Correct |
16 ms |
23808 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
16 ms |
23936 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
17 ms |
23936 KB |
Output is correct |
| 2 |
Correct |
16 ms |
23928 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
17 ms |
24064 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
16 ms |
24064 KB |
Output is correct |
| 2 |
Correct |
50 ms |
24064 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
93 ms |
24320 KB |
Output is correct |
| 2 |
Correct |
20 ms |
24320 KB |
Output is correct |
| 3 |
Correct |
22 ms |
24704 KB |
Too short sequence |
| 4 |
Correct |
467 ms |
24824 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
25 ms |
24320 KB |
Output is correct |
| 2 |
Correct |
343 ms |
24336 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
190 ms |
29688 KB |
Output is correct |
| 2 |
Correct |
51 ms |
26368 KB |
Output is correct |
| 3 |
Execution timed out |
1090 ms |
29816 KB |
Time limit exceeded |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
98 ms |
26360 KB |
Output is correct |
| 2 |
Execution timed out |
1088 ms |
26316 KB |
Time limit exceeded |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
938 ms |
34552 KB |
Output is correct |
| 2 |
Execution timed out |
1095 ms |
34424 KB |
Time limit exceeded |
| 3 |
Halted |
0 ms |
0 KB |
- |
