結果
問題 | No.1254 補強への架け橋 |
ユーザー |
|
提出日時 | 2020-10-09 23:06:45 |
言語 | C++17(gcc12) (gcc 12.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 325 ms / 2,000 ms |
コード長 | 7,311 bytes |
コンパイル時間 | 12,648 ms |
コンパイル使用メモリ | 308,488 KB |
最終ジャッジ日時 | 2025-01-15 05:44:00 |
ジャッジサーバーID (参考情報) |
judge4 / judge1 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 3 |
other | AC * 123 |
コンパイルメッセージ
main.cpp: In function 'int main()': main.cpp:236:18: warning: narrowing conversion of 'b' from 'll' {aka 'long long int'} to 'int' [-Wnarrowing] 236 | G[a].pb({b}); | ^ main.cpp:237:18: warning: narrowing conversion of 'a' from 'll' {aka 'long long int'} to 'int' [-Wnarrowing] 237 | G[b].pb({a}); | ^
ソースコード
#pragma GCC target("avx2") #pragma GCC optimize("O3") #pragma GCC optimize("unroll-loops") #include <bits/stdc++.h> constexpr long long INF = 1LL << 60; double PI = acos(-1.0); #define rep(i, n) for (ll i = 0; i < (n); ++i) #define rep1(i, n) for (ll i = 1; i <= (n); ++i) #define rrep(i, n) for (ll i = (n - 1); i >= 0; --i) #define perm(c) sort(ALL(c));for(bool c##p=1;c##p;c##p=next_permutation(ALL(c))) #define ALL(obj) (obj).begin(), (obj).end() #define RALL(obj) (obj).rbegin(), (obj).rend() #define pb push_back #define to_s to_string #define len(v) (ll)v.size() #define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end()) #define print(x) cout << (x) << '\n' #define drop(x) cout << (x) << '\n', exit(0) #define debug(x) cout << #x << ": " << (x) << '\n' using namespace std; typedef long long ll; typedef unsigned long long ull; typedef pair<ll, ll> P; typedef tuple<ll, ll, ll> tpl; typedef vector<ll> vec; typedef vector<vector<ll>> vec2; typedef vector<vector<vector<ll>>> vec3; template<class S, class T> inline bool chmax(S &a, const T &b) { if (a<b) { a=b; return 1; } return 0; } template<class S, class T> inline bool chmin(S &a, const T &b) { if (b<a) { a=b; return 1; } return 0; } inline ll msb(ll v) { return 1 << (31 - __builtin_clzll(v)); } inline ll devc(ll x, ll y) { return (x + y - 1) / y; } inline ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; } inline ll lcm(ll a, ll b) { return a * (b / gcd(a, b)); } struct IoSetup { IoSetup() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(10); cerr << fixed << setprecision(10); } } iosetup; template< typename T1, typename T2 > ostream &operator << (ostream &os, const pair< T1, T2 > &p) { os << p.first << " " << p.second; return os; } template< typename T1, typename T2 > istream &operator >> (istream &is, pair< T1, T2 > &p) { is >> p.first >> p.second; return is; } template< typename T1, typename T2, typename T3 > ostream &operator << (ostream &os, const tuple< T1, T2, T3 > &t) { os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t); return os; } template< typename T1, typename T2, typename T3 > istream &operator >> (istream &is, tuple< T1, T2, T3 > &t) { is >> get<0>(t) >> get<1>(t) >> get<2>(t); return is; } template< typename T > ostream &operator << (ostream &os, const vector< T > &v){ for (int i = 0; i < (int)v.size(); ++i) { os << v[i] << (i + 1 != v.size() ? " " : ""); } return os; } template< typename T > istream &operator >> (istream &is, vector< T > &v){ for(T &in : v) is >> in; return is; } template< typename T > ostream &operator << (ostream &os, const set< T > &st){ int ct = 0; for(auto& s : st) cout << s << (++ct != st.size() ? " " : ""); return os; } template <typename T> constexpr set<T> &operator|= (set<T> &st1, const set<T> &st2) { for(auto& s : st2) st1.insert(s); return st1; } template <typename T> constexpr set<T> &operator-= (set<T> &st1, const set<T> &st2) { for(auto& s : st2) if(st1.count(s)) st1.erase(s); return st1; } template <typename T> constexpr set<T> &operator&= (set<T> &st1, const set<T> &st2) { auto itr = st1.begin(); while(itr != st1.end()){ if(!st2.count(*itr)) itr = st1.erase(itr); else ++itr; } return st1; } template <typename T> constexpr set<T> operator| (const set<T> &st1, const set<T> &st2) { set<T> res = st1; res |= st2; return res; } template <typename T> constexpr set<T> operator- (const set<T> &st1, const set<T> &st2) { set<T> res = st1; res -= st2; return res; } template <typename T> constexpr set<T> operator& (const set<T> &st1, const set<T> &st2) { set<T> res = st1; res &= st2; return res; } /*--------------------------------- Tools ------------------------------------------*/ template< typename T > vector<T> cumsum(const vector<T> &X){ vector<T> res(X.size() + 1, 0); for(int i = 0; i < X.size(); ++i) res[i + 1] += res[i] + X[i]; return res; } template< typename S, typename T, typename F> pair<T, T> bisearch(S left, T right, F f) { while(abs(right - left) > 1){ T mid = (right + left) / 2; if(f(mid)) right = mid; else left = mid; } return {left, right}; } template< typename S, typename T, typename F> double trisearch(S left, T right, F f, int maxLoop = 90){ double low = left, high = right; while(maxLoop--){ double mid_left = high / 3 + low * 2 / 3; double mid_right = high * 2 / 3 + low / 3; if(f(mid_left) >= f(mid_right)) low = mid_left; else high = mid_right; } return (low + high) * 0.5; } template< typename F > ll ternarySearch(ll L, ll R, F f) { //[L, R) ll lo = L - 1, hi = R - 1; while (lo + 1 != hi) { ll mi = (lo + hi) / 2; if (f(mi) <= f(mi + 1)) hi = mi; else lo = mi; } return hi; } struct Edge { int to; }; using Graph = vector<vector<Edge>>; /* Lowlink: グラフの関節点・橋を列挙する構造体 作成: O(E+V) 関節点の集合: vector<int> aps 橋の集合: vector<P> bridges */ struct LowLink { const Graph &G; vector<int> used, ord, low; vector<int> aps; // articulation points vector<P> bridges; LowLink(const Graph &G_) : G(G_) { used.assign(G.size(), 0); ord.assign(G.size(), 0); low.assign(G.size(), 0); int k = 0; for (int i = 0; i < (int)G.size(); i++) { if (!used[i]) k = dfs(i, k, -1); } sort(aps.begin(), aps.end()); // 必要ならソートする sort(bridges.begin(), bridges.end()); // 必要ならソートする } int dfs(int id, int k, int par) { // id:探索中の頂点, k:dfsで何番目に探索するか, par:idの親 used[id] = true; ord[id] = k++; low[id] = ord[id]; bool is_aps = false; int count = 0; // 子の数 for (auto &e : G[id]) { if (!used[e.to]) { count++; k = dfs(e.to, k, id); low[id] = min(low[id], low[e.to]); if (par != -1 && ord[id] <= low[e.to]) is_aps = true; // 条件2を満たすので関節点 if (ord[id] < low[e.to]) bridges.emplace_back(min(id, e.to), max(id, e.to)); } else if (e.to != par) { // eが後退辺の時 low[id] = min(low[id], ord[e.to]); } } if (par == -1 && count >= 2) is_aps = true; // 条件1を満たすので関節点 if (is_aps) aps.push_back(id); return k; } }; // #include <atcoder/all> // using namespace atcoder; constexpr long long MOD = 1000000007; /*------------------------------- Main Code Here -----------------------------------------*/ int main() { ll N; cin >> N; Graph G(N); map<P, ll> bridge; rep(i, N){ ll a, b; cin >> a >> b; --a, --b; G[a].pb({b}); G[b].pb({a}); bridge[{a, b}] = i; bridge[{b, a}] = i; } LowLink LK(G); set<ll> ans; rep1(i, N) ans.insert(i); for(auto p : LK.bridges){ ans.erase(bridge[p] + 1); } print(len(ans)); print(ans); return 0; }