#include <bits/stdc++.h> using namespace std; using ll = long long; #ifdef LOCAL #include "debug.h" #else #define debug(...) 2137 #endif // https://github.com/kth-competitive-programming/kactl/blob/main/content/graph/LinkCutTree.h struct Node { // Splay tree. Root's pp contains tree's parent. Node *p = 0, *pp = 0, *c[2]; bool flip = 0; Node() { c[0] = c[1] = 0; fix(); } void fix() { if (c[0]) c[0]->p = this; if (c[1]) c[1]->p = this; // (+ update sum of subtree elements etc. if wanted) } void pushFlip() { if (!flip) return; flip = 0; swap(c[0], c[1]); if (c[0]) c[0]->flip ^= 1; if (c[1]) c[1]->flip ^= 1; } int up() { return p ? p->c[1] == this : -1; } void rot(int i, int b) { int h = i ^ b; Node *x = c[i], *y = b == 2 ? x : x->c[h], *z = b ? y : x; if ((y->p = p)) p->c[up()] = y; c[i] = z->c[i ^ 1]; if (b < 2) { x->c[h] = y->c[h ^ 1]; y->c[h ^ 1] = x; } z->c[i ^ 1] = this; fix(); x->fix(); y->fix(); if (p) p->fix(); swap(pp, y->pp); } void splay() { /// Splay this up to the root. Always finishes without flip set. for (pushFlip(); p; ) { if (p->p) p->p->pushFlip(); p->pushFlip(); pushFlip(); int c1 = up(), c2 = p->up(); if (c2 == -1) p->rot(c1, 2); else p->p->rot(c2, c1 != c2); } } Node* first() { /// Return the min element of the subtree rooted at this, splayed to the top. pushFlip(); return c[0] ? c[0]->first() : (splay(), this); } }; struct LinkCut { vector<Node> node; LinkCut(int N) : node(N) {} void link(int u, int v) { // add an edge (u, v) assert(!connected(u, v)); makeRoot(&node[u]); node[u].pp = &node[v]; } void cut(int u, int v) { // remove an edge (u, v) Node *x = &node[u], *top = &node[v]; makeRoot(top); x->splay(); assert(top == (x->pp ?: x->c[0])); if (x->pp) x->pp = 0; else { x->c[0] = top->p = 0; x->fix(); } } bool connected(int u, int v) { // are u, v in the same tree? Node* nu = access(&node[u])->first(); return nu == access(&node[v])->first(); } void makeRoot(Node* u) { /// Move u to root of represented tree. access(u); u->splay(); if(u->c[0]) { u->c[0]->p = 0; u->c[0]->flip ^= 1; u->c[0]->pp = u; u->c[0] = 0; u->fix(); } } Node* access(Node* u) { /// Move u to root aux tree. Return the root of the root aux tree. u->splay(); while (Node* pp = u->pp) { pp->splay(); u->pp = 0; if (pp->c[1]) { pp->c[1]->p = 0; pp->c[1]->pp = pp; } pp->c[1] = u; pp->fix(); u = pp; } return u; } }; const int N = 300300; int n, q; set<int> adj[N]; LinkCut lct(0); char typ[N]; vector<int> id; void dfs(int u, int p) { id.push_back(u); for (int v : adj[u]) { if (v != p) { dfs(v, u); } } } void napraw(int a) { // iter po ludziach w tym // ustawiamy im 1, usuwamy wszystkie kraw // zeby uzyskac numer noda wystarczy odjac lct.node.begin() bo to tablica id.clear(); dfs(a, -1); for (int i : id) { for (int j : adj[i]) { adj[j].erase(i); lct.cut(i, j); } adj[i].clear(); typ[i] = '1'; } } int main() { ios_base::sync_with_stdio(false); cin.tie(nullptr); cin >> n >> q; lct = LinkCut(n); for (int i = 0; i < n; i++) { typ[i] = '0'; } string ans; ans.reserve(q); for (int it = 0; it < q; it++) { char c; cin >> c; if (c == '+') { int a, b; cin >> a >> b; a--; b--; if (lct.connected(a, b)) { napraw(a); } else { if (typ[a] == '1') { napraw(b); } else if (typ[b] == '1') { napraw(a); } else { lct.link(a, b); adj[a].insert(b); adj[b].insert(a); typ[a] = typ[b] = '?'; } } } else if (c == '-') { int a; cin >> a; a--; if (ssize(adj[a]) > 1) { // nie lisc for (int b : adj[a]) { adj[b].erase(a); lct.cut(a, b); } int bb = *adj[a].begin(); for (int b : adj[a]) { if (b != bb) { lct.link(b, bb); adj[b].insert(bb); adj[bb].insert(b); } } adj[a].clear(); typ[a] = '0'; } else if (ssize(adj[a]) == 1) { // lisc typ[a] = '0'; int b = *adj[a].begin(); if (ssize(adj[b]) == 1) { typ[b] = '0'; } adj[a].clear(); adj[b].erase(a); lct.cut(a, b); } else { typ[a] = '0'; } } else { int a; cin >> a; ans += typ[a - 1]; } } cout << ans << '\n'; }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 | #include <bits/stdc++.h> using namespace std; using ll = long long; #ifdef LOCAL #include "debug.h" #else #define debug(...) 2137 #endif // https://github.com/kth-competitive-programming/kactl/blob/main/content/graph/LinkCutTree.h struct Node { // Splay tree. Root's pp contains tree's parent. Node *p = 0, *pp = 0, *c[2]; bool flip = 0; Node() { c[0] = c[1] = 0; fix(); } void fix() { if (c[0]) c[0]->p = this; if (c[1]) c[1]->p = this; // (+ update sum of subtree elements etc. if wanted) } void pushFlip() { if (!flip) return; flip = 0; swap(c[0], c[1]); if (c[0]) c[0]->flip ^= 1; if (c[1]) c[1]->flip ^= 1; } int up() { return p ? p->c[1] == this : -1; } void rot(int i, int b) { int h = i ^ b; Node *x = c[i], *y = b == 2 ? x : x->c[h], *z = b ? y : x; if ((y->p = p)) p->c[up()] = y; c[i] = z->c[i ^ 1]; if (b < 2) { x->c[h] = y->c[h ^ 1]; y->c[h ^ 1] = x; } z->c[i ^ 1] = this; fix(); x->fix(); y->fix(); if (p) p->fix(); swap(pp, y->pp); } void splay() { /// Splay this up to the root. Always finishes without flip set. for (pushFlip(); p; ) { if (p->p) p->p->pushFlip(); p->pushFlip(); pushFlip(); int c1 = up(), c2 = p->up(); if (c2 == -1) p->rot(c1, 2); else p->p->rot(c2, c1 != c2); } } Node* first() { /// Return the min element of the subtree rooted at this, splayed to the top. pushFlip(); return c[0] ? c[0]->first() : (splay(), this); } }; struct LinkCut { vector<Node> node; LinkCut(int N) : node(N) {} void link(int u, int v) { // add an edge (u, v) assert(!connected(u, v)); makeRoot(&node[u]); node[u].pp = &node[v]; } void cut(int u, int v) { // remove an edge (u, v) Node *x = &node[u], *top = &node[v]; makeRoot(top); x->splay(); assert(top == (x->pp ?: x->c[0])); if (x->pp) x->pp = 0; else { x->c[0] = top->p = 0; x->fix(); } } bool connected(int u, int v) { // are u, v in the same tree? Node* nu = access(&node[u])->first(); return nu == access(&node[v])->first(); } void makeRoot(Node* u) { /// Move u to root of represented tree. access(u); u->splay(); if(u->c[0]) { u->c[0]->p = 0; u->c[0]->flip ^= 1; u->c[0]->pp = u; u->c[0] = 0; u->fix(); } } Node* access(Node* u) { /// Move u to root aux tree. Return the root of the root aux tree. u->splay(); while (Node* pp = u->pp) { pp->splay(); u->pp = 0; if (pp->c[1]) { pp->c[1]->p = 0; pp->c[1]->pp = pp; } pp->c[1] = u; pp->fix(); u = pp; } return u; } }; const int N = 300300; int n, q; set<int> adj[N]; LinkCut lct(0); char typ[N]; vector<int> id; void dfs(int u, int p) { id.push_back(u); for (int v : adj[u]) { if (v != p) { dfs(v, u); } } } void napraw(int a) { // iter po ludziach w tym // ustawiamy im 1, usuwamy wszystkie kraw // zeby uzyskac numer noda wystarczy odjac lct.node.begin() bo to tablica id.clear(); dfs(a, -1); for (int i : id) { for (int j : adj[i]) { adj[j].erase(i); lct.cut(i, j); } adj[i].clear(); typ[i] = '1'; } } int main() { ios_base::sync_with_stdio(false); cin.tie(nullptr); cin >> n >> q; lct = LinkCut(n); for (int i = 0; i < n; i++) { typ[i] = '0'; } string ans; ans.reserve(q); for (int it = 0; it < q; it++) { char c; cin >> c; if (c == '+') { int a, b; cin >> a >> b; a--; b--; if (lct.connected(a, b)) { napraw(a); } else { if (typ[a] == '1') { napraw(b); } else if (typ[b] == '1') { napraw(a); } else { lct.link(a, b); adj[a].insert(b); adj[b].insert(a); typ[a] = typ[b] = '?'; } } } else if (c == '-') { int a; cin >> a; a--; if (ssize(adj[a]) > 1) { // nie lisc for (int b : adj[a]) { adj[b].erase(a); lct.cut(a, b); } int bb = *adj[a].begin(); for (int b : adj[a]) { if (b != bb) { lct.link(b, bb); adj[b].insert(bb); adj[bb].insert(b); } } adj[a].clear(); typ[a] = '0'; } else if (ssize(adj[a]) == 1) { // lisc typ[a] = '0'; int b = *adj[a].begin(); if (ssize(adj[b]) == 1) { typ[b] = '0'; } adj[a].clear(); adj[b].erase(a); lct.cut(a, b); } else { typ[a] = '0'; } } else { int a; cin >> a; ans += typ[a - 1]; } } cout << ans << '\n'; } |