#include <iostream> #include <vector> #include <queue> #include <map> using namespace std; struct Edge { Edge(long long c1, long long c2) : c1(c1), c2(c2) {} long long c1, c2; }; ostream &operator<<(ostream &s, const Edge &e) { return s << '(' << e.c1 << ", " << e.c2 << ')'; } bool operator==(const Edge &e1, const Edge &e2) { return e1.c1 == e2.c1 and e1.c2 == e2.c2; } bool operator<(const Edge &e1, const Edge &e2) { if (e1.c1 == e2.c1) { return e1.c2 < e2.c2; } return e1.c2 < e2.c2; }; struct City { long long price; vector<int> neighbors; }; long long MIN = -2000000000000000000; struct EdgeValue { long long cost = 0; long long profit = MIN; int direction = -1; }; ostream &operator<<(ostream &s, const EdgeValue &v) { return s << '(' << v.cost << ", " << v.profit << ", " << v.direction << ')'; } int n, q; int city = 0; vector<City> cities; map<Edge, EdgeValue> edges; Edge getEdge(int c1, int c2) { if (c1 < c2) { return {c1, c2}; } else { return {c2, c1}; } } void show() { cerr << ">>>>>>>>>>>" << endl; for (int i = 0; i < n; i++) { cerr << i << " " << cities[i].price << " {"; for (int n : cities[i].neighbors) { cerr << n << ","; } cerr << "}" << endl; } cerr << "city: " << city << endl; for (auto it : edges) cerr << " " << it.first << ":" << it.second << endl; cerr << "<<<<<<<<<<<<<<<<" << endl; } void update(int c, int parent) { if (parent >= 0) { long long profit = cities[c].price; for (int n : cities[c].neighbors) { if (n != parent) { profit = max(profit, edges[getEdge(c,n)].profit); } } EdgeValue& ev = edges[getEdge(c, parent)]; ev.profit = profit - ev.cost; ev.direction = parent; } } void dfs(int c, int parent, bool visited[]) { visited[c] = true; for (int n : cities[c].neighbors) { if (!visited[n]) { dfs(n, c, visited); } } if (parent >= 0) { update(c, parent); } } void init() { bool *visited = new bool[n]; for (int i = 0; i < n; i++) { visited[i] = false; } dfs(city, -1, visited); } void update(int c) { for (int n : cities[c].neighbors) { if (edges[getEdge(c,n)].direction != c) { update(c, n); update(n); return; } } } void doChange(int c, long long change) { cities[c].price = change; update(c); } void doChange(const int c1, int c2, long long change) { EdgeValue& ev = edges[getEdge(c1,c2)]; ev.cost = change; update(c1 == ev.direction ? c2 : c1); } void go(int c, int parent) { long long max; int direction; if (parent < 0) { direction = -1; max = MIN; } else { max = cities[c].price; direction = c; } for (int n : cities[c].neighbors) { EdgeValue& ev = edges[getEdge(c,n)]; if (n != parent && (ev.profit > max || (ev.profit == max && n < direction))) { direction = n; max = ev.profit; } } if (direction == c) { city = c; } else { update(c, direction); go(direction, c); } } int main() { cin.sync_with_stdio(false); cin.tie(nullptr); cin >> n >> q; cities.resize(n); for (int i = 0; i < n; i++) { cin >> cities[i].price; } for (int i = 0; i < n-1; i++) { int c1, c2; long long cost; cin >> c1 >> c2; cin >> cost; edges[getEdge(c1-1, c2-1)].cost = cost; cities[c1-1].neighbors.push_back(c2-1); cities[c2-1].neighbors.push_back(c1-1); } init(); for (int i = 0; i < q; i++) { int kind; long long change; cin >> kind; if (kind == 1) { int c; cin >> c >> change; doChange(c-1, change); } else { int c1, c2; cin >> c1 >> c2 >> change; doChange(c1-1, c2-1, change); } go(city, -1); cout << city + 1; if (i == q-1) { cout << endl; } else { cout << " "; } } }
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 | #include <iostream> #include <vector> #include <queue> #include <map> using namespace std; struct Edge { Edge(long long c1, long long c2) : c1(c1), c2(c2) {} long long c1, c2; }; ostream &operator<<(ostream &s, const Edge &e) { return s << '(' << e.c1 << ", " << e.c2 << ')'; } bool operator==(const Edge &e1, const Edge &e2) { return e1.c1 == e2.c1 and e1.c2 == e2.c2; } bool operator<(const Edge &e1, const Edge &e2) { if (e1.c1 == e2.c1) { return e1.c2 < e2.c2; } return e1.c2 < e2.c2; }; struct City { long long price; vector<int> neighbors; }; long long MIN = -2000000000000000000; struct EdgeValue { long long cost = 0; long long profit = MIN; int direction = -1; }; ostream &operator<<(ostream &s, const EdgeValue &v) { return s << '(' << v.cost << ", " << v.profit << ", " << v.direction << ')'; } int n, q; int city = 0; vector<City> cities; map<Edge, EdgeValue> edges; Edge getEdge(int c1, int c2) { if (c1 < c2) { return {c1, c2}; } else { return {c2, c1}; } } void show() { cerr << ">>>>>>>>>>>" << endl; for (int i = 0; i < n; i++) { cerr << i << " " << cities[i].price << " {"; for (int n : cities[i].neighbors) { cerr << n << ","; } cerr << "}" << endl; } cerr << "city: " << city << endl; for (auto it : edges) cerr << " " << it.first << ":" << it.second << endl; cerr << "<<<<<<<<<<<<<<<<" << endl; } void update(int c, int parent) { if (parent >= 0) { long long profit = cities[c].price; for (int n : cities[c].neighbors) { if (n != parent) { profit = max(profit, edges[getEdge(c,n)].profit); } } EdgeValue& ev = edges[getEdge(c, parent)]; ev.profit = profit - ev.cost; ev.direction = parent; } } void dfs(int c, int parent, bool visited[]) { visited[c] = true; for (int n : cities[c].neighbors) { if (!visited[n]) { dfs(n, c, visited); } } if (parent >= 0) { update(c, parent); } } void init() { bool *visited = new bool[n]; for (int i = 0; i < n; i++) { visited[i] = false; } dfs(city, -1, visited); } void update(int c) { for (int n : cities[c].neighbors) { if (edges[getEdge(c,n)].direction != c) { update(c, n); update(n); return; } } } void doChange(int c, long long change) { cities[c].price = change; update(c); } void doChange(const int c1, int c2, long long change) { EdgeValue& ev = edges[getEdge(c1,c2)]; ev.cost = change; update(c1 == ev.direction ? c2 : c1); } void go(int c, int parent) { long long max; int direction; if (parent < 0) { direction = -1; max = MIN; } else { max = cities[c].price; direction = c; } for (int n : cities[c].neighbors) { EdgeValue& ev = edges[getEdge(c,n)]; if (n != parent && (ev.profit > max || (ev.profit == max && n < direction))) { direction = n; max = ev.profit; } } if (direction == c) { city = c; } else { update(c, direction); go(direction, c); } } int main() { cin.sync_with_stdio(false); cin.tie(nullptr); cin >> n >> q; cities.resize(n); for (int i = 0; i < n; i++) { cin >> cities[i].price; } for (int i = 0; i < n-1; i++) { int c1, c2; long long cost; cin >> c1 >> c2; cin >> cost; edges[getEdge(c1-1, c2-1)].cost = cost; cities[c1-1].neighbors.push_back(c2-1); cities[c2-1].neighbors.push_back(c1-1); } init(); for (int i = 0; i < q; i++) { int kind; long long change; cin >> kind; if (kind == 1) { int c; cin >> c >> change; doChange(c-1, change); } else { int c1, c2; cin >> c1 >> c2 >> change; doChange(c1-1, c2-1, change); } go(city, -1); cout << city + 1; if (i == q-1) { cout << endl; } else { cout << " "; } } } |