#include<iostream> #include<list> #include<iterator> #include<algorithm> #include<vector> #include<stack> #include<map> using namespace std; void displayAdjList(map<int, list<int>> &adj_list) { for (const auto& pair : adj_list) { cout << pair.first << "--->"; for (int val : pair.second) { cout << val << " "; } cout << endl; } } void add_edge(map<int, list<int>> &adj_list, int u, int v) { adj_list[u].push_back(v); adj_list[v].push_back(u); } bool can_you_connect(int dest, int source, map<int, list<int>> &graph) { int destAndSourceCounter = 0; for (auto it = graph[source].begin(); it != graph[source].end(); ++it) { for (auto ij = graph[*it].begin(); ij != graph[*it].end(); ++ij) { if(*ij == dest) { destAndSourceCounter++; } else if(*ij == source) { destAndSourceCounter++; } if(destAndSourceCounter == 2) { return true; } } destAndSourceCounter = 0; } return false; } void recursive_search(int dest, map<int, list<int>> &graph, vector<pair<int, int>> &changes, stack<int> &visited) { if(visited.empty()) { return; } int source = visited.top(); if(can_you_connect(dest, source, graph)) { pair<int, int> p = {source, dest}; changes.push_back(p); add_edge(graph, source, dest); visited.pop(); if(visited.empty()) { return; } recursive_search(dest, graph, changes, visited); } else { for (auto it = graph[source].begin(); it != graph[source].end(); ++it) { visited.push(*it); recursive_search(dest, graph, changes, visited); if (!visited.empty()) { visited.pop(); } else { return; } } } } int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); int n, connections, desiredConnections; cin >> n; cin >> connections; map<int, list<int>> graph; map<int, list<int>> desired_graph; vector<pair<int, int>> performConns; int first, sec; for(int i = 0; i < connections; i++) { cin >> first >> sec; add_edge(graph, first, sec); } cin >> desiredConnections; int j = 0; pair<int, int> performConnPair; for(int i = 0; i < desiredConnections; i++) { cin >> first >> sec; add_edge(desired_graph, first, sec); auto iter = find(graph[first].begin(), graph[first].end(), sec); if (iter == graph[first].end()) { performConnPair.first = first; performConnPair.second = sec; performConns.push_back(performConnPair); } } vector<pair<int, int>> changes; vector<pair<int, int>> removeEdgesChanges; stack<int> visited; for(int i = 0; i < (desiredConnections - connections); i++) { visited.push(performConns[i].first); recursive_search(performConns[i].second, graph, changes, visited); } pair<int, int> removeEvent; for(int i = 0; i < changes.size(); i++) { auto iter = find(desired_graph[changes[i].first].begin(), desired_graph[changes[i].first].end(), changes[i].second); if (iter == desired_graph[changes[i].first].end()) { removeEvent = {changes[i].first, changes[i].second}; removeEdgesChanges.push_back(removeEvent); } } cout << (changes.size() + removeEdgesChanges.size()) << "\n"; for(int i = 0; i < changes.size(); i++) { cout << "+ " << changes[i].first << " " << changes[i].second << "\n"; } for(int i = 0; i < removeEdgesChanges.size(); i++) { cout << "- " << removeEdgesChanges[i].first << " " << removeEdgesChanges[i].second << "\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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 | #include<iostream> #include<list> #include<iterator> #include<algorithm> #include<vector> #include<stack> #include<map> using namespace std; void displayAdjList(map<int, list<int>> &adj_list) { for (const auto& pair : adj_list) { cout << pair.first << "--->"; for (int val : pair.second) { cout << val << " "; } cout << endl; } } void add_edge(map<int, list<int>> &adj_list, int u, int v) { adj_list[u].push_back(v); adj_list[v].push_back(u); } bool can_you_connect(int dest, int source, map<int, list<int>> &graph) { int destAndSourceCounter = 0; for (auto it = graph[source].begin(); it != graph[source].end(); ++it) { for (auto ij = graph[*it].begin(); ij != graph[*it].end(); ++ij) { if(*ij == dest) { destAndSourceCounter++; } else if(*ij == source) { destAndSourceCounter++; } if(destAndSourceCounter == 2) { return true; } } destAndSourceCounter = 0; } return false; } void recursive_search(int dest, map<int, list<int>> &graph, vector<pair<int, int>> &changes, stack<int> &visited) { if(visited.empty()) { return; } int source = visited.top(); if(can_you_connect(dest, source, graph)) { pair<int, int> p = {source, dest}; changes.push_back(p); add_edge(graph, source, dest); visited.pop(); if(visited.empty()) { return; } recursive_search(dest, graph, changes, visited); } else { for (auto it = graph[source].begin(); it != graph[source].end(); ++it) { visited.push(*it); recursive_search(dest, graph, changes, visited); if (!visited.empty()) { visited.pop(); } else { return; } } } } int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); int n, connections, desiredConnections; cin >> n; cin >> connections; map<int, list<int>> graph; map<int, list<int>> desired_graph; vector<pair<int, int>> performConns; int first, sec; for(int i = 0; i < connections; i++) { cin >> first >> sec; add_edge(graph, first, sec); } cin >> desiredConnections; int j = 0; pair<int, int> performConnPair; for(int i = 0; i < desiredConnections; i++) { cin >> first >> sec; add_edge(desired_graph, first, sec); auto iter = find(graph[first].begin(), graph[first].end(), sec); if (iter == graph[first].end()) { performConnPair.first = first; performConnPair.second = sec; performConns.push_back(performConnPair); } } vector<pair<int, int>> changes; vector<pair<int, int>> removeEdgesChanges; stack<int> visited; for(int i = 0; i < (desiredConnections - connections); i++) { visited.push(performConns[i].first); recursive_search(performConns[i].second, graph, changes, visited); } pair<int, int> removeEvent; for(int i = 0; i < changes.size(); i++) { auto iter = find(desired_graph[changes[i].first].begin(), desired_graph[changes[i].first].end(), changes[i].second); if (iter == desired_graph[changes[i].first].end()) { removeEvent = {changes[i].first, changes[i].second}; removeEdgesChanges.push_back(removeEvent); } } cout << (changes.size() + removeEdgesChanges.size()) << "\n"; for(int i = 0; i < changes.size(); i++) { cout << "+ " << changes[i].first << " " << changes[i].second << "\n"; } for(int i = 0; i < removeEdgesChanges.size(); i++) { cout << "- " << removeEdgesChanges[i].first << " " << removeEdgesChanges[i].second << "\n"; } return 0; } |