#include <cstdio> #include <set> using namespace std; int n, ms, md, i, a, b, op_id; set<int> conn_s[30001]; set<int> conn_d[30001]; int visited[30001]; char op[200001]; int op_a[200001]; int op_b[200001]; void build_skeleton(int node) { if (visited[node] != 1) { visited[node] = 1; if (node != n) { if (conn_s[node].find(n) == conn_s[node].end()) { op[op_id] = '+'; op_a[op_id] = n; op_b[op_id] = node; op_id++; conn_s[node].insert(n); conn_s[n].insert(node); } } for (set<int>::iterator it = conn_s[node].begin(); it != conn_s[node].end(); it++) { build_skeleton(*it); } } } void remove_unnecessary(int node) { if (visited[node] != 2) { visited[node] = 2; for (set<int>::iterator it = conn_d[node].begin(); it != conn_d[node].end(); it++) { remove_unnecessary(*it); } set<int>::iterator it = conn_s[node].begin(); while (it != conn_s[node].end()) { // if needed to be deleted, connection with "n" will be deleted at the end, we need that behaviour (and we have it, set is sorted in ascending order) if (conn_d[node].find(*it) == conn_d[node].end()) { int x = *it; op[op_id] = '-'; op_a[op_id] = node; op_b[op_id] = x; op_id++; it++; conn_s[node].erase(x); conn_s[x].erase(node); } else { it++; } } } } int main() { op_id = 0; scanf("%d", &n); for (i = 1; i <= n; i++) { visited[i] = 0; } scanf("%d", &ms); for (i = 0; i < ms; i++) { scanf("%d %d", &a, &b); conn_s[a].insert(b); conn_s[b].insert(a); } scanf("%d", &md); for (i = 0; i < md; i++) { scanf("%d %d", &a, &b); conn_d[a].insert(b); conn_d[b].insert(a); } // 1. connect all nodes with node "n" build_skeleton(n); // 2. build missing connections for (i = 1; i <= n; i++) { for (set<int>::iterator it = conn_d[i].begin(); it != conn_d[i].end(); it++) { if (conn_s[i].find(*it) == conn_s[i].end()) { op[op_id] = '+'; op_a[op_id] = i; op_b[op_id] = *it; op_id++; conn_s[i].insert(*it); conn_s[*it].insert(i); } } } // 3. remove unnecessary connections (from the "end" of destination graph) remove_unnecessary(n); printf("%d\n", op_id); for (i = 0; i < op_id; i++) { printf("%c %d %d\n", op[i], op_a[i], op_b[i]); } 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 | #include <cstdio> #include <set> using namespace std; int n, ms, md, i, a, b, op_id; set<int> conn_s[30001]; set<int> conn_d[30001]; int visited[30001]; char op[200001]; int op_a[200001]; int op_b[200001]; void build_skeleton(int node) { if (visited[node] != 1) { visited[node] = 1; if (node != n) { if (conn_s[node].find(n) == conn_s[node].end()) { op[op_id] = '+'; op_a[op_id] = n; op_b[op_id] = node; op_id++; conn_s[node].insert(n); conn_s[n].insert(node); } } for (set<int>::iterator it = conn_s[node].begin(); it != conn_s[node].end(); it++) { build_skeleton(*it); } } } void remove_unnecessary(int node) { if (visited[node] != 2) { visited[node] = 2; for (set<int>::iterator it = conn_d[node].begin(); it != conn_d[node].end(); it++) { remove_unnecessary(*it); } set<int>::iterator it = conn_s[node].begin(); while (it != conn_s[node].end()) { // if needed to be deleted, connection with "n" will be deleted at the end, we need that behaviour (and we have it, set is sorted in ascending order) if (conn_d[node].find(*it) == conn_d[node].end()) { int x = *it; op[op_id] = '-'; op_a[op_id] = node; op_b[op_id] = x; op_id++; it++; conn_s[node].erase(x); conn_s[x].erase(node); } else { it++; } } } } int main() { op_id = 0; scanf("%d", &n); for (i = 1; i <= n; i++) { visited[i] = 0; } scanf("%d", &ms); for (i = 0; i < ms; i++) { scanf("%d %d", &a, &b); conn_s[a].insert(b); conn_s[b].insert(a); } scanf("%d", &md); for (i = 0; i < md; i++) { scanf("%d %d", &a, &b); conn_d[a].insert(b); conn_d[b].insert(a); } // 1. connect all nodes with node "n" build_skeleton(n); // 2. build missing connections for (i = 1; i <= n; i++) { for (set<int>::iterator it = conn_d[i].begin(); it != conn_d[i].end(); it++) { if (conn_s[i].find(*it) == conn_s[i].end()) { op[op_id] = '+'; op_a[op_id] = i; op_b[op_id] = *it; op_id++; conn_s[i].insert(*it); conn_s[*it].insert(i); } } } // 3. remove unnecessary connections (from the "end" of destination graph) remove_unnecessary(n); printf("%d\n", op_id); for (i = 0; i < op_id; i++) { printf("%c %d %d\n", op[i], op_a[i], op_b[i]); } return 0; } |