#include <iostream> #include <list> #include <queue> using namespace std; long long distances[100001]; class Path { public: int target = 0; long long cost = 0; Path(int t = 0, long long c = 0) { this -> target = t; this -> cost = c; } }; class Compare { public: bool operator() (int a, int b) { return (distances[a] == -1) || distances[a] > distances[b]; } }; int main() { list<Path> p[100001]; priority_queue<long long, std::deque<long long>, Compare> Q; long long z[100001]; int n, q; cin >> n >> q; for(int i = 0; i < n; i++) { cin >> z[i+1]; } for(int i = 0; i < n-1; i++) { int a, b; long long c; cin >> a >> b >> c; p[a].push_back(Path(b, c)); p[b].push_back(Path(a, c)); } int current = 1; for(int i = 0; i < q; i++) { //getting and updating changes int type; cin >> type; if(type == 1) { int v, d; cin >> v >> d; z[v] = d; } else { int a, b, d; cin >> a >> b >> d; for(list<Path>::iterator it = p[a].begin(); it != p[a].end(); ++it) { if((*it).target == b) { (*it).cost = d; break; } } for(list<Path>::iterator it = p[b].begin(); it != p[b].end(); ++it) { if((*it).target == a) { (*it).cost = d; break; } } } //dijkstra for(int j = 0; j < n; j++) { distances[j+1] = -1; } distances[current] = 0; for(int j = 0; j < n; j++) { Q.push(j+1); } while (!Q.empty()) { int u = Q.top(); Q.pop(); for(list<Path>::iterator it = p[u].begin(); it != p[u].end(); ++it) { int v = (*it).target; if(distances[v] == -1 || distances[v] > distances[u] + (*it).cost) { distances[v] = distances[u] + (*it).cost; Q.push(v); } } } int best = -1; for(int j = 0; j < n; j++) { if(j+1 == current) continue; if(best == -1 || distances[j+1] - z[j+1] < distances[best] - z[best]) { best = j+1; } } current = best; cout << current; if(i < q-1) cout << " "; } cout << endl; 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 | #include <iostream> #include <list> #include <queue> using namespace std; long long distances[100001]; class Path { public: int target = 0; long long cost = 0; Path(int t = 0, long long c = 0) { this -> target = t; this -> cost = c; } }; class Compare { public: bool operator() (int a, int b) { return (distances[a] == -1) || distances[a] > distances[b]; } }; int main() { list<Path> p[100001]; priority_queue<long long, std::deque<long long>, Compare> Q; long long z[100001]; int n, q; cin >> n >> q; for(int i = 0; i < n; i++) { cin >> z[i+1]; } for(int i = 0; i < n-1; i++) { int a, b; long long c; cin >> a >> b >> c; p[a].push_back(Path(b, c)); p[b].push_back(Path(a, c)); } int current = 1; for(int i = 0; i < q; i++) { //getting and updating changes int type; cin >> type; if(type == 1) { int v, d; cin >> v >> d; z[v] = d; } else { int a, b, d; cin >> a >> b >> d; for(list<Path>::iterator it = p[a].begin(); it != p[a].end(); ++it) { if((*it).target == b) { (*it).cost = d; break; } } for(list<Path>::iterator it = p[b].begin(); it != p[b].end(); ++it) { if((*it).target == a) { (*it).cost = d; break; } } } //dijkstra for(int j = 0; j < n; j++) { distances[j+1] = -1; } distances[current] = 0; for(int j = 0; j < n; j++) { Q.push(j+1); } while (!Q.empty()) { int u = Q.top(); Q.pop(); for(list<Path>::iterator it = p[u].begin(); it != p[u].end(); ++it) { int v = (*it).target; if(distances[v] == -1 || distances[v] > distances[u] + (*it).cost) { distances[v] = distances[u] + (*it).cost; Q.push(v); } } } int best = -1; for(int j = 0; j < n; j++) { if(j+1 == current) continue; if(best == -1 || distances[j+1] - z[j+1] < distances[best] - z[best]) { best = j+1; } } current = best; cout << current; if(i < q-1) cout << " "; } cout << endl; return 0; } |