/* * Copyright (C) 2015 Paweł Widera * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details: * http://www.gnu.org/licenses/gpl.html */ #include <vector> #include <deque> #include <unordered_set> #include <tuple> #include <algorithm> #include <iostream> using namespace std; // breadth-first search - checks if a path from source to target exists // and fills the vector of distances from source bool is_path(int source, int target, vector<vector<int>>& neighbours, vector<vector<int>>& capacity, vector<int>& distance) { for (unsigned int i=0; i < distance.size(); ++i) { distance[i] = -999; } deque<int> queue; queue.push_back(source); distance[source] = 0; while (!queue.empty()) { int current = queue.front(); queue.pop_front(); for (auto node: neighbours[current]) { if (distance[node] < 0 && capacity[current][node] > 0) { distance[node] = distance[current] + 1; queue.push_back(node); } } } if (distance[target] < 0) { return false; } return true; } // depth first search - finds a flow increasing path int dfs(int current, int target, int min_capacity, vector<vector<int>>& neighbours, vector<vector<int>>& capacity, vector<int>& distance, vector<unsigned int>& first) { if (current == target || min_capacity == 0) { return min_capacity; } int total_flow = 0; for (unsigned int& i = first[current]; i < neighbours[current].size(); ++i) { int next = neighbours[current][i]; // use only distance increasing edges of non-zero capacity if (distance[next] == distance[current] + 1 && capacity[current][next] > 0) { // continue path from next and find its max flow int flow = dfs(next, target, min(min_capacity, capacity[current][next]), neighbours, capacity, distance, first); // move the capacity of used edges to the reversed edges capacity[current][next] -= flow; capacity[next][current] += flow; min_capacity -= flow; total_flow += flow; if (min_capacity == 0) { break; } } } return total_flow; } // adds graph edge (two directional) and its weight (capacity) void add_edge(int a, int b, int weight, vector<vector<int>>& neighbours, vector<vector<int>>& capacity) { capacity[a][b] = weight; neighbours[a].push_back(b); neighbours[b].push_back(a); } int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int n, m; cin >> n >> m; vector<tuple<int, int, int>> tasks; tasks.reserve(n); unordered_set<int> timepoints; int start, stop, duration; int total_duration = 0; for (int i = 0; i < n; ++i) { cin >> start >> stop >> duration; tasks.push_back(make_tuple(start, stop, duration)); total_duration += duration; timepoints.insert(start); timepoints.insert(stop); } // sort the time points vector<int> points(begin(timepoints), end(timepoints)); sort(begin(points), end(points)); int nodes = points.size() + n + 1; vector<vector<int>> neighbours(nodes); vector<int> distance(nodes, -999); vector<vector<int>> capacity(nodes, vector<int>(nodes, 0)); int max_capacity = 0; // add edges from source node for (int i = 1; i < (int)points.size(); ++i) { int weight = m * (points[i] - points[i - 1]); max_capacity = max(weight, max_capacity); add_edge(0, i, weight, neighbours, capacity); } // add edges to target node for (int i = 0; i < n; ++i) { int weight = get<2>(tasks[i]); max_capacity = max(weight, max_capacity); add_edge(points.size() + i, nodes - 1, weight, neighbours, capacity); } // add inner edges for (int i = 1; i < (int)points.size(); ++i) { for (int j = 0; j < n; ++j) { // points are between ready time and deadline if (points[i - 1] >= get<0>(tasks[j]) && points[i] <= get<1>(tasks[j])) { int weight = (points[i] - points[i - 1]); max_capacity = max(weight, max_capacity); add_edge(i, points.size() + j, weight, neighbours, capacity); } } } int max_flow = 0; while (is_path(0, nodes - 1, neighbours, capacity, distance)) { vector<unsigned int> first(nodes, 0); max_flow += dfs(0, nodes - 1, max_capacity, neighbours, capacity, distance, first); } string answer = "NIE"; if (max_flow == total_duration) { answer = "TAK"; } cout << answer << 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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 | /* * Copyright (C) 2015 Paweł Widera * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details: * http://www.gnu.org/licenses/gpl.html */ #include <vector> #include <deque> #include <unordered_set> #include <tuple> #include <algorithm> #include <iostream> using namespace std; // breadth-first search - checks if a path from source to target exists // and fills the vector of distances from source bool is_path(int source, int target, vector<vector<int>>& neighbours, vector<vector<int>>& capacity, vector<int>& distance) { for (unsigned int i=0; i < distance.size(); ++i) { distance[i] = -999; } deque<int> queue; queue.push_back(source); distance[source] = 0; while (!queue.empty()) { int current = queue.front(); queue.pop_front(); for (auto node: neighbours[current]) { if (distance[node] < 0 && capacity[current][node] > 0) { distance[node] = distance[current] + 1; queue.push_back(node); } } } if (distance[target] < 0) { return false; } return true; } // depth first search - finds a flow increasing path int dfs(int current, int target, int min_capacity, vector<vector<int>>& neighbours, vector<vector<int>>& capacity, vector<int>& distance, vector<unsigned int>& first) { if (current == target || min_capacity == 0) { return min_capacity; } int total_flow = 0; for (unsigned int& i = first[current]; i < neighbours[current].size(); ++i) { int next = neighbours[current][i]; // use only distance increasing edges of non-zero capacity if (distance[next] == distance[current] + 1 && capacity[current][next] > 0) { // continue path from next and find its max flow int flow = dfs(next, target, min(min_capacity, capacity[current][next]), neighbours, capacity, distance, first); // move the capacity of used edges to the reversed edges capacity[current][next] -= flow; capacity[next][current] += flow; min_capacity -= flow; total_flow += flow; if (min_capacity == 0) { break; } } } return total_flow; } // adds graph edge (two directional) and its weight (capacity) void add_edge(int a, int b, int weight, vector<vector<int>>& neighbours, vector<vector<int>>& capacity) { capacity[a][b] = weight; neighbours[a].push_back(b); neighbours[b].push_back(a); } int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int n, m; cin >> n >> m; vector<tuple<int, int, int>> tasks; tasks.reserve(n); unordered_set<int> timepoints; int start, stop, duration; int total_duration = 0; for (int i = 0; i < n; ++i) { cin >> start >> stop >> duration; tasks.push_back(make_tuple(start, stop, duration)); total_duration += duration; timepoints.insert(start); timepoints.insert(stop); } // sort the time points vector<int> points(begin(timepoints), end(timepoints)); sort(begin(points), end(points)); int nodes = points.size() + n + 1; vector<vector<int>> neighbours(nodes); vector<int> distance(nodes, -999); vector<vector<int>> capacity(nodes, vector<int>(nodes, 0)); int max_capacity = 0; // add edges from source node for (int i = 1; i < (int)points.size(); ++i) { int weight = m * (points[i] - points[i - 1]); max_capacity = max(weight, max_capacity); add_edge(0, i, weight, neighbours, capacity); } // add edges to target node for (int i = 0; i < n; ++i) { int weight = get<2>(tasks[i]); max_capacity = max(weight, max_capacity); add_edge(points.size() + i, nodes - 1, weight, neighbours, capacity); } // add inner edges for (int i = 1; i < (int)points.size(); ++i) { for (int j = 0; j < n; ++j) { // points are between ready time and deadline if (points[i - 1] >= get<0>(tasks[j]) && points[i] <= get<1>(tasks[j])) { int weight = (points[i] - points[i - 1]); max_capacity = max(weight, max_capacity); add_edge(i, points.size() + j, weight, neighbours, capacity); } } } int max_flow = 0; while (is_path(0, nodes - 1, neighbours, capacity, distance)) { vector<unsigned int> first(nodes, 0); max_flow += dfs(0, nodes - 1, max_capacity, neighbours, capacity, distance, first); } string answer = "NIE"; if (max_flow == total_duration) { answer = "TAK"; } cout << answer << endl; return 0; } |