#include <bits/stdc++.h> using namespace std; typedef pair<int,int> pii; typedef unordered_set<int> usi; constexpr int ONE = 1; // only for visual distinction (special vertex) void add_one_to_all(int n, vector<usi>& graph_s, vector<pii>& additions) { usi to_add; queue<int> q; for (int i = 2; i <= n; i++) { if (graph_s[ONE].count(i) == 0) to_add.insert(i); else q.push(i); } while (to_add.size()) { int v = q.front(); q.pop(); for (auto u : graph_s[v]) { if (to_add.count(u)) { to_add.erase(u); q.push(u); additions.push_back({ONE, u}); graph_s[ONE].insert(u), graph_s[u].insert(ONE); } } } } void handle_differences(int n, vector<usi>& graph_s, vector<usi>& graph_d, vector<pii>& additions, vector<pii>& deletions) { for (int v = 2; v <= n; v++) { for (auto u : graph_d[v]) { if (graph_s[v].count(u) == 0) { graph_s[v].insert(u); if (u > v) additions.push_back({u, v}); } } } for (int v = 2; v <= n; v++) { for (auto u : graph_s[v]) if (u != ONE && graph_d[v].count(u) == 0) if (u > v) deletions.push_back({u, v}); } for (auto [v, u] : deletions) graph_s[v].erase(u), graph_s[u].erase(v); } void remove_redundant_ones(int n, vector<usi>& graph_s, vector<usi>& graph_d, vector<pii>& deletions) { int previous_deletions = deletions.size(); usi to_delete; queue<int> q; for (int i = 2; i <= n; i++) { if (graph_d[ONE].count(i) == 0) to_delete.insert(i); else q.push(i); } while (to_delete.size()) { int v = q.front(); q.pop(); for (auto u : graph_d[v]) { if (to_delete.count(u)) { to_delete.erase(u); q.push(u); deletions.push_back({ONE, u}); graph_s[ONE].erase(u), graph_s[u].erase(ONE); } } } reverse(deletions.begin() + previous_deletions, deletions.end()); } int main() { ios_base::sync_with_stdio(0); cin.tie(0); int n, m_s, m_d; cin >> n >> m_s; vector<usi> graph_s(n+1), graph_d(n+1); for (int i = 0; i < m_s; i++) { int a, b; cin >> a >> b; graph_s[a].insert(b); graph_s[b].insert(a); } cin >> m_d; for (int i = 0; i < m_d; i++) { int a, b; cin >> a >> b; graph_d[a].insert(b); graph_d[b].insert(a); } vector<pii> additions, deletions; add_one_to_all(n, graph_s, additions); handle_differences(n, graph_s, graph_d, additions, deletions); remove_redundant_ones(n, graph_s, graph_d, deletions); cout << additions.size() + deletions.size() << '\n'; for (auto [a, b] : additions) cout << "+ " << a << ' ' << b << '\n'; for (auto [a, b] : deletions) cout << "- " << a << ' ' << b << '\n'; return 0; }
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 | #include <bits/stdc++.h> using namespace std; typedef pair<int,int> pii; typedef unordered_set<int> usi; constexpr int ONE = 1; // only for visual distinction (special vertex) void add_one_to_all(int n, vector<usi>& graph_s, vector<pii>& additions) { usi to_add; queue<int> q; for (int i = 2; i <= n; i++) { if (graph_s[ONE].count(i) == 0) to_add.insert(i); else q.push(i); } while (to_add.size()) { int v = q.front(); q.pop(); for (auto u : graph_s[v]) { if (to_add.count(u)) { to_add.erase(u); q.push(u); additions.push_back({ONE, u}); graph_s[ONE].insert(u), graph_s[u].insert(ONE); } } } } void handle_differences(int n, vector<usi>& graph_s, vector<usi>& graph_d, vector<pii>& additions, vector<pii>& deletions) { for (int v = 2; v <= n; v++) { for (auto u : graph_d[v]) { if (graph_s[v].count(u) == 0) { graph_s[v].insert(u); if (u > v) additions.push_back({u, v}); } } } for (int v = 2; v <= n; v++) { for (auto u : graph_s[v]) if (u != ONE && graph_d[v].count(u) == 0) if (u > v) deletions.push_back({u, v}); } for (auto [v, u] : deletions) graph_s[v].erase(u), graph_s[u].erase(v); } void remove_redundant_ones(int n, vector<usi>& graph_s, vector<usi>& graph_d, vector<pii>& deletions) { int previous_deletions = deletions.size(); usi to_delete; queue<int> q; for (int i = 2; i <= n; i++) { if (graph_d[ONE].count(i) == 0) to_delete.insert(i); else q.push(i); } while (to_delete.size()) { int v = q.front(); q.pop(); for (auto u : graph_d[v]) { if (to_delete.count(u)) { to_delete.erase(u); q.push(u); deletions.push_back({ONE, u}); graph_s[ONE].erase(u), graph_s[u].erase(ONE); } } } reverse(deletions.begin() + previous_deletions, deletions.end()); } int main() { ios_base::sync_with_stdio(0); cin.tie(0); int n, m_s, m_d; cin >> n >> m_s; vector<usi> graph_s(n+1), graph_d(n+1); for (int i = 0; i < m_s; i++) { int a, b; cin >> a >> b; graph_s[a].insert(b); graph_s[b].insert(a); } cin >> m_d; for (int i = 0; i < m_d; i++) { int a, b; cin >> a >> b; graph_d[a].insert(b); graph_d[b].insert(a); } vector<pii> additions, deletions; add_one_to_all(n, graph_s, additions); handle_differences(n, graph_s, graph_d, additions, deletions); remove_redundant_ones(n, graph_s, graph_d, deletions); cout << additions.size() + deletions.size() << '\n'; for (auto [a, b] : additions) cout << "+ " << a << ' ' << b << '\n'; for (auto [a, b] : deletions) cout << "- " << a << ' ' << b << '\n'; return 0; } |