#include <bits/stdc++.h>
using namespace std;
struct Event {
bool type;
int v, w;
};
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
// input
int V;
cin >> V;
int E1;
cin >> E1;
vector<set<int>> adj1(V);
for (int i = 0; i < E1; i++) {
int v, w;
cin >> v >> w;
v--, w--;
adj1[v].insert(w);
adj1[w].insert(v);
}
int E2;
cin >> E2;
vector<set<int>> adj2(V);
for (int i = 0; i < E2; i++) {
int v, w;
cin >> v >> w;
v--, w--;
adj2[v].insert(w);
adj2[w].insert(v);
}
vector<Event> result;
// find bfs order in graph1
vector<int> order;
order.reserve(V);
queue<int> toVisit;
toVisit.push(0);
vector<bool> visited(V, false);
visited[0] = true;
while (not toVisit.empty()) {
int v = toVisit.front();
toVisit.pop();
order.push_back(v);
for (int w: adj1[v])
if (not visited[w]) {
visited[w] = true;
toVisit.push(w);
}
}
// add star
for (int i = 1; i < V; i++) {
auto find = adj1[0].find(order[i]);
if (find == adj1[0].end())
result.push_back({true, 0, order[i]});
}
// add edges
for (int v = 1; v < V; v++)
for (int w: adj2[v]) {
if (w == 0 or w < v)
continue;
auto find = adj1[v].find(w);
if (find == adj1[v].end())
result.push_back({true, v, w});
}
// remove edges
for (int v = 1; v < V; v++)
for (int w: adj1[v]) {
if (w == 0 or w < v)
continue;
auto find = adj2[v].find(w);
if (find == adj2[v].end())
result.push_back({false, v, w});
}
// find bfs order in graph2
order.clear();
order.reserve(V);
toVisit.push(0);
visited.assign(V, false);
visited[0] = true;
while (not toVisit.empty()) {
int v = toVisit.front();
toVisit.pop();
order.push_back(v);
for (int w: adj2[v])
if (not visited[w]) {
visited[w] = true;
toVisit.push(w);
}
}
// remove star
for (int i = V - 1; i >= 1; i--) {
auto find = adj2[0].find(order[i]);
if (find == adj2[0].end())
result.push_back({false, 0, order[i]});
}
// output
cout << result.size() << "\n";
for (auto &event: result)
cout << (event.type ? "+ " : "- ") << event.v + 1 << " " << event.w + 1 << "\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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 | #include <bits/stdc++.h> using namespace std; struct Event { bool type; int v, w; }; int main() { ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); // input int V; cin >> V; int E1; cin >> E1; vector<set<int>> adj1(V); for (int i = 0; i < E1; i++) { int v, w; cin >> v >> w; v--, w--; adj1[v].insert(w); adj1[w].insert(v); } int E2; cin >> E2; vector<set<int>> adj2(V); for (int i = 0; i < E2; i++) { int v, w; cin >> v >> w; v--, w--; adj2[v].insert(w); adj2[w].insert(v); } vector<Event> result; // find bfs order in graph1 vector<int> order; order.reserve(V); queue<int> toVisit; toVisit.push(0); vector<bool> visited(V, false); visited[0] = true; while (not toVisit.empty()) { int v = toVisit.front(); toVisit.pop(); order.push_back(v); for (int w: adj1[v]) if (not visited[w]) { visited[w] = true; toVisit.push(w); } } // add star for (int i = 1; i < V; i++) { auto find = adj1[0].find(order[i]); if (find == adj1[0].end()) result.push_back({true, 0, order[i]}); } // add edges for (int v = 1; v < V; v++) for (int w: adj2[v]) { if (w == 0 or w < v) continue; auto find = adj1[v].find(w); if (find == adj1[v].end()) result.push_back({true, v, w}); } // remove edges for (int v = 1; v < V; v++) for (int w: adj1[v]) { if (w == 0 or w < v) continue; auto find = adj2[v].find(w); if (find == adj2[v].end()) result.push_back({false, v, w}); } // find bfs order in graph2 order.clear(); order.reserve(V); toVisit.push(0); visited.assign(V, false); visited[0] = true; while (not toVisit.empty()) { int v = toVisit.front(); toVisit.pop(); order.push_back(v); for (int w: adj2[v]) if (not visited[w]) { visited[w] = true; toVisit.push(w); } } // remove star for (int i = V - 1; i >= 1; i--) { auto find = adj2[0].find(order[i]); if (find == adj2[0].end()) result.push_back({false, 0, order[i]}); } // output cout << result.size() << "\n"; for (auto &event: result) cout << (event.type ? "+ " : "- ") << event.v + 1 << " " << event.w + 1 << "\n"; return 0; } |
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