#include <bits/stdc++.h> using namespace std; set <pair <int, int > > edges, edgesFinal; vector <int> G[30006], path; bool odw[30006]; struct ops { string s; int a, b; }; vector <ops> result; void add_edge(int a, int b) { result.push_back({"+ ", a, b}); //cout <<"+ " << a << " " << b << "\n"; } void delete_edge(int a, int b) { edges.erase({a,b}); result.push_back({"- ", a, b}); // cout <<"- " << a << " " << b << "\n"; } void dfs(int u) { odw[u] = true; for (auto v : G[u]) { if (odw[v] == false) { if (edges.find({1, v}) == edges.end()) { edges.insert({1, v}); add_edge(1, v); } dfs(v); } } } void dfs2(int u) { odw[u] = true; path.push_back(u); for (auto v : G[u]) { if (odw[v] == false) dfs2(v); } } int main() { ios_base::sync_with_stdio(0); int n, m1, m2; cin >> n; cin >> m1; for (int i = 1; i <= m1; i++) { int a, b; cin >> a >> b; G[a].push_back(b); G[b].push_back(a); if (a > b) swap(a, b); edges.insert({a, b}); } cin >> m2; for (int i = 1; i <= m2; i++) { int a, b; cin >> a >> b; if (a > b) swap(a, b); edgesFinal.insert({a,b}); } dfs(1); for (int i = 2; i <= n; i++) odw[i] = false; int start = 0; // add additional for (auto e : edgesFinal) { if (edges.find(e) == edges.end()) { add_edge(e.first, e.second); } if (e.first == 1) start = e.second; } // delete vector <pair <int, int> > edgesCopy; for (auto e : edges) edgesCopy.push_back(e); for (auto e : edgesCopy) { if (e.first != 1) if (edgesFinal.find(e) == edgesFinal.end()) { delete_edge(e.first, e.second); } } dfs2(start); for (auto p : path) { if (edgesFinal.find({1,p}) == edgesFinal.end()) { delete_edge(1, p); } } cout << result.size() << "\n"; for (auto r : result) { cout << r.s << r.a << " " << r.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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 | #include <bits/stdc++.h> using namespace std; set <pair <int, int > > edges, edgesFinal; vector <int> G[30006], path; bool odw[30006]; struct ops { string s; int a, b; }; vector <ops> result; void add_edge(int a, int b) { result.push_back({"+ ", a, b}); //cout <<"+ " << a << " " << b << "\n"; } void delete_edge(int a, int b) { edges.erase({a,b}); result.push_back({"- ", a, b}); // cout <<"- " << a << " " << b << "\n"; } void dfs(int u) { odw[u] = true; for (auto v : G[u]) { if (odw[v] == false) { if (edges.find({1, v}) == edges.end()) { edges.insert({1, v}); add_edge(1, v); } dfs(v); } } } void dfs2(int u) { odw[u] = true; path.push_back(u); for (auto v : G[u]) { if (odw[v] == false) dfs2(v); } } int main() { ios_base::sync_with_stdio(0); int n, m1, m2; cin >> n; cin >> m1; for (int i = 1; i <= m1; i++) { int a, b; cin >> a >> b; G[a].push_back(b); G[b].push_back(a); if (a > b) swap(a, b); edges.insert({a, b}); } cin >> m2; for (int i = 1; i <= m2; i++) { int a, b; cin >> a >> b; if (a > b) swap(a, b); edgesFinal.insert({a,b}); } dfs(1); for (int i = 2; i <= n; i++) odw[i] = false; int start = 0; // add additional for (auto e : edgesFinal) { if (edges.find(e) == edges.end()) { add_edge(e.first, e.second); } if (e.first == 1) start = e.second; } // delete vector <pair <int, int> > edgesCopy; for (auto e : edges) edgesCopy.push_back(e); for (auto e : edgesCopy) { if (e.first != 1) if (edgesFinal.find(e) == edgesFinal.end()) { delete_edge(e.first, e.second); } } dfs2(start); for (auto p : path) { if (edgesFinal.find({1,p}) == edgesFinal.end()) { delete_edge(1, p); } } cout << result.size() << "\n"; for (auto r : result) { cout << r.s << r.a << " " << r.b << "\n"; } return 0; } |