#include <algorithm> #include <cstdio> #include <iterator> #include <map> #include <queue> #include <set> #include <utility> #include <vector> using namespace std; vector<vector<int>> sgraph, dgraph, supergraph; set<pair<int, int>> sedges, dedges; vector<pair<int, int>> smissing, dmissing; int ADD = 0, MINUS = 1; class Event { public: int type; int a; int b; Event(int type, int a, int b) : type(type), a(a), b(b) {} }; vector<int> bfs_path(const vector<vector<int>>& graph, int a, int b) { queue<int> Q; map<int, int> back; Q.push(a); while (not Q.empty()) { int c = Q.front(); if (c == b) { break; } Q.pop(); for (int nei : graph[c]) { if (back.find(nei) == back.end()) { Q.push(nei); back[nei] = c; } } } vector<int> result; while (b != a) { result.push_back(b); b = back[b]; } result.push_back(a); return vector<int>(result.rbegin(), result.rend()); } void read_graph(vector<vector<int>>& graph, set<pair<int, int>>& edges){ int m, a, b; scanf("%d", &m); while (m--) { scanf("%d%d", &a, &b); a--; b--; if (a > b) swap(a, b); edges.insert(make_pair(a, b)); graph[a].push_back(b); graph[b].push_back(a); } } pair<int, int> pop_shortest_edge( vector<pair<int, int>>& edges, const vector<vector<int>>& graph, vector<pair<int, int>>& add_stack, const set<pair<int, int>>& actual_edges ) { pair<int, int> pseudo_shortest = *edges.rbegin(); do_again: vector<int> path = bfs_path(graph, pseudo_shortest.first, pseudo_shortest.second); for (int i = 2; i < path.size() - 1; i++) { auto p = make_pair(path[0], path[i]); if (actual_edges.count(p)) { pseudo_shortest = p; add_stack.clear(); goto do_again; } add_stack.push_back(p); } if (pseudo_shortest == *edges.rbegin()) { edges.pop_back(); return pseudo_shortest; } edges.erase(std::find(edges.begin(), edges.end(), pseudo_shortest)); return pseudo_shortest; } void compute_sequence(vector<pair<int, int>>& edges, const vector<vector<int>>& graph, int inverse, vector<Event>& result) { set<pair<int, int>> edges_(edges.begin(), edges.end()); random_shuffle(edges.begin(), edges.end()); vector<pair<int, int>> drop_stack, add_stack; while (!edges.empty()) { pair<int, int> edge = pop_shortest_edge(edges, graph, add_stack, edges_); for (const auto& pair: add_stack) { result.push_back(Event(ADD ^ inverse, pair.first, pair.second)); drop_stack.push_back(pair); } result.push_back(Event(ADD ^ inverse, edge.first, edge.second)); add_stack.clear(); } for (const auto& pair : drop_stack) { result.push_back(Event(MINUS ^ inverse, pair.first, pair.second)); } } int main() { int n; scanf("%d", &n); sgraph.resize(n); dgraph.resize(n); read_graph(sgraph, sedges); read_graph(dgraph, dedges); set_difference(dedges.begin(), dedges.end(), sedges.begin(), sedges.end(), back_inserter(smissing)); set_difference(sedges.begin(), sedges.end(), dedges.begin(), dedges.end(), back_inserter(dmissing)); vector<Event> result, rev_result; compute_sequence(smissing, sgraph, 0, result); compute_sequence(dmissing, dgraph, 1, rev_result); printf("%d\n", (int)(result.size() + rev_result.size())); for (const Event& event : result) { printf("%c %d %d\n", (event.type == ADD ? '+' : '-'), event.a + 1, event.b + 1); } for (auto it = rev_result.rbegin(); it != rev_result.rend(); it++) { printf("%c %d %d\n", (it->type == ADD ? '+' : '-'), it->a + 1, it->b + 1); } 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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 | #include <algorithm> #include <cstdio> #include <iterator> #include <map> #include <queue> #include <set> #include <utility> #include <vector> using namespace std; vector<vector<int>> sgraph, dgraph, supergraph; set<pair<int, int>> sedges, dedges; vector<pair<int, int>> smissing, dmissing; int ADD = 0, MINUS = 1; class Event { public: int type; int a; int b; Event(int type, int a, int b) : type(type), a(a), b(b) {} }; vector<int> bfs_path(const vector<vector<int>>& graph, int a, int b) { queue<int> Q; map<int, int> back; Q.push(a); while (not Q.empty()) { int c = Q.front(); if (c == b) { break; } Q.pop(); for (int nei : graph[c]) { if (back.find(nei) == back.end()) { Q.push(nei); back[nei] = c; } } } vector<int> result; while (b != a) { result.push_back(b); b = back[b]; } result.push_back(a); return vector<int>(result.rbegin(), result.rend()); } void read_graph(vector<vector<int>>& graph, set<pair<int, int>>& edges){ int m, a, b; scanf("%d", &m); while (m--) { scanf("%d%d", &a, &b); a--; b--; if (a > b) swap(a, b); edges.insert(make_pair(a, b)); graph[a].push_back(b); graph[b].push_back(a); } } pair<int, int> pop_shortest_edge( vector<pair<int, int>>& edges, const vector<vector<int>>& graph, vector<pair<int, int>>& add_stack, const set<pair<int, int>>& actual_edges ) { pair<int, int> pseudo_shortest = *edges.rbegin(); do_again: vector<int> path = bfs_path(graph, pseudo_shortest.first, pseudo_shortest.second); for (int i = 2; i < path.size() - 1; i++) { auto p = make_pair(path[0], path[i]); if (actual_edges.count(p)) { pseudo_shortest = p; add_stack.clear(); goto do_again; } add_stack.push_back(p); } if (pseudo_shortest == *edges.rbegin()) { edges.pop_back(); return pseudo_shortest; } edges.erase(std::find(edges.begin(), edges.end(), pseudo_shortest)); return pseudo_shortest; } void compute_sequence(vector<pair<int, int>>& edges, const vector<vector<int>>& graph, int inverse, vector<Event>& result) { set<pair<int, int>> edges_(edges.begin(), edges.end()); random_shuffle(edges.begin(), edges.end()); vector<pair<int, int>> drop_stack, add_stack; while (!edges.empty()) { pair<int, int> edge = pop_shortest_edge(edges, graph, add_stack, edges_); for (const auto& pair: add_stack) { result.push_back(Event(ADD ^ inverse, pair.first, pair.second)); drop_stack.push_back(pair); } result.push_back(Event(ADD ^ inverse, edge.first, edge.second)); add_stack.clear(); } for (const auto& pair : drop_stack) { result.push_back(Event(MINUS ^ inverse, pair.first, pair.second)); } } int main() { int n; scanf("%d", &n); sgraph.resize(n); dgraph.resize(n); read_graph(sgraph, sedges); read_graph(dgraph, dedges); set_difference(dedges.begin(), dedges.end(), sedges.begin(), sedges.end(), back_inserter(smissing)); set_difference(sedges.begin(), sedges.end(), dedges.begin(), dedges.end(), back_inserter(dmissing)); vector<Event> result, rev_result; compute_sequence(smissing, sgraph, 0, result); compute_sequence(dmissing, dgraph, 1, rev_result); printf("%d\n", (int)(result.size() + rev_result.size())); for (const Event& event : result) { printf("%c %d %d\n", (event.type == ADD ? '+' : '-'), event.a + 1, event.b + 1); } for (auto it = rev_result.rbegin(); it != rev_result.rend(); it++) { printf("%c %d %d\n", (it->type == ADD ? '+' : '-'), it->a + 1, it->b + 1); } return 0; } |