結果

問題 No.2674 k-Walk on Bipartite
ユーザー umimel
提出日時 2024-03-15 23:16:50
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 230 ms / 2,000 ms
コード長 4,054 bytes
コンパイル時間 2,026 ms
コンパイル使用メモリ 183,784 KB
実行使用メモリ 35,712 KB
最終ジャッジ日時 2024-09-30 02:50:14
合計ジャッジ時間 5,385 ms
ジャッジサーバーID
(参考情報)
judge2 / judge3
このコードへのチャレンジ
(要ログイン)
ファイルパターン 結果
sample AC * 3
other AC * 36
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;
#define drep(i, cc, n) for (ll i = (cc); i <= (n); ++i)
#define rep(i, n) drep(i, 0, n - 1)
#define all(a) (a).begin(), (a).end()
#define pb push_back
#define fi first
#define se second
mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());
const ll MOD1000000007 = 1000000007;
const ll MOD998244353 = 998244353;
const ll MOD[3] = {999727999, 1070777777, 1000000007};
const ll LINF = 1LL << 60LL;
const int IINF = (1 << 30) - 1;
template<typename T>
struct edge{
int from, to;
T cost;
int id;
edge(){}
edge(int to, T cost=1) : from(-1), to(to), cost(cost){}
edge(int to, T cost, int id) : from(-1), to(to), cost(cost), id(id){}
edge(int from, int to, T cost, int id) : from(from), to(to), cost(cost), id(id){}
};
template<typename T>
struct redge{
int from, to;
T cap, cost;
int rev;
redge(int to, T cap, T cost=(T)(1)) : from(-1), to(to), cap(cap), cost(cost){}
redge(int to, T cap, T cost, int rev) : from(-1), to(to), cap(cap), cost(cost), rev(rev){}
};
template<typename T> using Edges = vector<edge<T>>;
template<typename T> using weighted_graph = vector<Edges<T>>;
template<typename T> using tree = vector<Edges<T>>;
using unweighted_graph = vector<vector<int>>;
template<typename T> using residual_graph = vector<vector<redge<T>>>;
vector<long long> dijkstra(weighted_graph<long long> G, int src){
int n = (int)G.size();
vector<long long> dist(n, LINF);
dist[src] = 0;
priority_queue<pair<long long, int>, vector<pair<long long, int>>, greater<pair<long long, int>>> PQ;
PQ.push({0, src});
while(!PQ.empty()){
int v = PQ.top().second;
long long tmp = PQ.top().first;
PQ.pop();
if(dist[v] < tmp) continue;
for(edge<long long> e : G[v]){
if(dist[v]+e.cost < dist[e.to]){
dist[e.to] = dist[v]+e.cost;
PQ.push({dist[e.to], e.to});
}
}
}
return dist;
}
struct union_find{
vector<int> par;
vector<int> siz;
union_find(int n) : par(n), siz(n, 1){
for(int i=0; i<n; i++) par[i] = i;
}
int root(int x){
if (par[x] == x) return x;
return par[x] = root(par[x]);
}
void unite(int x, int y){
int rx = root(x);
int ry = root(y);
if (rx == ry) return;
if (siz[rx] < siz[ry]) swap(rx, ry);
siz[rx] += siz[ry];
par[ry] = rx;
}
bool same(int x, int y){
int rx = root(x);
int ry = root(y);
return rx == ry;
}
int size(int x){
return siz[root(x)];
}
};
void solve(){
int n, m; cin >> n >> m;
int s, t, k; cin >> s >> t >> k;
s--; t--;
weighted_graph<ll> G(n);
union_find uf(n);
for(int i=0; i<m; i++){
int u, v; cin >> u >> v;
u--; v--;
G[u].pb(edge<ll>(v));
G[v].pb(edge<ll>(u));
uf.unite(u, v);
}
if(s==t){
if(k%2==1){
cout << "No\n";
}else{
if(uf.size(s)>=2){
cout << "Yes\n";
}else{
if(n==1){
cout << "No\n";
}else if(n>=2){
cout << "Unknown\n";
}
}
}
return;
}
if(!uf.same(s, t)){
if(n>=3){
cout << "Unknown\n";
}else if(n==2){
if(k%2==1){
cout << "Unknown\n";
}else{
cout << "No\n";
}
}else if(n==1){
cout << "No\n";
}
return;
}
vector<ll> dist = dijkstra(G, s);
if(dist[t]%2 != k%2){
cout << "No\n";
}else{
if(dist[t]<=k){
cout << "Yes\n";
}else{
cout << "Unknown\n";
}
}
}
int main(){
cin.tie(nullptr);
ios::sync_with_stdio(false);
int T=1;
//cin >> T;
while(T--) solve();
}
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