제출 #635293

#제출 시각아이디문제언어결과실행 시간메모리
635293GusterGoose27Port Facility (JOI17_port_facility)C++11
100 / 100
1914 ms615112 KiB
#include <bits/stdc++.h> using namespace std; const int MAXN = 1e6; const int inf = 1e9; const int MOD = 1e9+7; int n; int atl[2*MAXN]; int atr[2*MAXN]; vector<int> deact; class mintree { public: int mn = inf; mintree *l = nullptr; mintree *r = nullptr; int lp, rp; mintree(int lv, int rv, int arr[]) { lp = lv; rp = rv; if (lp == rp) { if (arr[lp] != -1) mn = arr[lp]; } else { int m = (lp+rp)/2; l = new mintree(lp, m, arr); r = new mintree(m+1, rp, arr); mn = min(l->mn, r->mn); } } int query(int lv, int rv) { if (lp > rv || rp < lv) return inf; if (lp >= lv && rp <= rv) return mn; return min(l->query(lv, rv), r->query(lv, rv)); } void upd(int p, int v) { if (lp > p || rp < p) return; if (lp == rp) { if (v == -1) mn = inf; else mn = v; return; } l->upd(p, v); r->upd(p, v); mn = min(l->mn, r->mn); } int l_contain(int l_lim, int l_req) { if (rp < l_lim || mn >= l_req) return inf; if (lp == rp) return lp; int ans = l->l_contain(l_lim, l_req); if (ans < inf) return ans; return r->l_contain(l_lim, l_req); } }; class maxtree { public: int mx = -1; maxtree *l = nullptr; maxtree *r = nullptr; int lp, rp; maxtree(int lv, int rv, int arr[]) { lp = lv; rp = rv; if (lp == rp) { mx = arr[lp]; } else { int m = (lp+rp)/2; l = new maxtree(lp, m, arr); r = new maxtree(m+1, rp, arr); mx = max(l->mx, r->mx); } } int query(int lv, int rv) { if (lp > rv || rp < lv) return -1; if (lp >= lv && rp <= rv) return mx; return max(l->query(lv, rv), r->query(lv, rv)); } void upd(int p, int v) { if (lp > p || rp < p) return; if (lp == rp) { mx = v; return; } l->upd(p, v); r->upd(p, v); mx = max(l->mx, r->mx); } }; mintree *close_contain; // min left maxtree *far_inter; // max right mintree *close_inter; // min left int uf[MAXN]; int sz[MAXN]; bool flip[MAXN]; int id[2*MAXN]; int find(int i) { if (uf[i] == -1) return i; int np = find(uf[i]); flip[i] ^= flip[uf[i]]; return uf[i] = np; } void merge(int a, int b, bool f) { int ia = find(a); int ib = find(b); if (ia == ib) { if ((flip[a]^flip[b]) != f) { cout << '0' << endl; exit(0); } return; } uf[ib] = ia; sz[ia] += sz[ib]; flip[ib] = flip[a]^flip[b]^f; } int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); cin >> n; fill(atl, atl+2*n, -1); fill(atr, atr+2*n, -1); fill(uf, uf+n, -1); fill(sz, sz+n, 1); for (int i = 0; i < n; i++) { int l, r; cin >> l >> r; l--; r--; atr[l] = r; atl[r] = l; id[l] = id[r] = i; } close_contain = new mintree(0, 2*n-1, atl); far_inter = new maxtree(0, 2*n-1, atr); close_inter = new mintree(0, 2*n-1, atl); for (int i = 0; i < 2*n; i++) { if (atr[i] == -1) continue; int r_cont = close_contain->l_contain(atr[i]+1, i); assert(r_cont > atr[i]); if (r_cont < inf) { int mx_r = far_inter->query(i, atr[i]); if (mx_r > r_cont) merge(id[i], id[r_cont], 0); } int lp = close_inter->query(atr[i]+1, r_cont-1); while (lp <= atr[i]) { deact.push_back(lp); merge(id[i], id[lp], 1); close_inter->upd(atr[lp], -1); lp = close_inter->query(atr[i]+1, r_cont-1); } for (int v: deact) close_inter->upd(atr[v], v); deact.clear(); } int ans = 1; for (int i = 0; i < n; i++) { if (uf[i] == -1) { ans *= 2; ans %= MOD; } } cout << ans << "\n"; }
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