/* * Copyright (C) 2020 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 <iostream> #include <string> #include <algorithm> #include <vector> #include <deque> #include <chrono> #include <unordered_map> using namespace std; #ifdef DEBUG template<typename... ArgTypes> inline void debug_print(ArgTypes... args) { using expand = int[]; (void)expand{0, ((cerr << args << " "), void(), 0)... }; cerr << endl; } #define DBG(...) debug_print(__VA_ARGS__); #define DBGx(x) cerr << #x << " " << x << endl; #define DBGa(array) cerr << #array << " "; for (auto a: array) { cerr << a << " "; } cerr << endl; #else #define DBG(...) #define DBGx(x) #define DBGa(array) #endif #define MAX_COST 1000000000 #define MAX_DISTANCE 4000000000000000 struct Cost { int up; int down; int operator<(const Cost& other) const { if (up == other.up) { return down < other.down; } else { return up < other.up; } } bool operator==(const Cost& other) const { return up == other.up && down == other.down; } }; struct Neighbour { int dx; int dy; }; const Neighbour NEIGHBOURHOOD[] = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}}; long long int find_shortest_path(int target, const Cost& cost, const vector<deque<int>>& graph) { vector<long long int> distances(target + 1, -1); distances[0] = 0; deque<pair<int, int>> queue; queue.push_back(make_pair(0, 0)); while (!queue.empty()) { int current = queue.front().first; queue.pop_front(); if (current == target) { continue; } for (auto node: graph[current]) { int weight = node > current ? cost.up : cost.down; long long int d = distances[current] + weight; //DBG("next=", node, " d=", d, "current=", current) if (distances[node] < 0) { distances[node] = d; queue.push_back(make_pair(node, d)); } else if (d < distances[node] + weight) { distances[node] = d; } } sort(queue.begin(), queue.end(), [](pair<int,int> a, pair<int,int> b){ return a.second < b.second; }); } return distances[target]; } int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int n, m, k; string row; int cost_up, cost_down; vector<string> map; vector<Cost> costs; cin >> n >> m >> k; map.reserve(n); costs.reserve(k); for (int i = 0; i < n; ++i) { cin >> row; map.emplace_back(row); } for (int i = 0; i < k; ++i) { cin >> cost_up >> cost_down; costs.push_back({cost_up, cost_down}); } auto start_time = chrono::high_resolution_clock::now(); // construct a graph (list of neighbours) vector<deque<int>> graph(n * m); for (int r = 0; r < n; ++r) { for (int c = 0; c < m; ++c) { if (map[r][c] == 'X') { continue; } int node = r * m + c; for (auto next: NEIGHBOURHOOD) { int x = c + next.dx; int y = r + next.dy; if (0 <= x && x < m && 0 <= y && y < n && map[y][x] != 'X') { graph[node].push_back(y * m + x); } } } } vector<Cost> unique_costs; vector<int> repeats; stable_sort(costs.begin(), costs.end()); for (auto cost: costs) { int index = unique_costs.size() - 1; if (!unique_costs.empty() && unique_costs[index] == cost) { repeats[index] += 1; } else { unique_costs.push_back(cost); repeats.push_back(1); } } // version A: for each climber run full dijkstra // version B: find 3 paths: for 2 divergent low,high and high,low // and 1 equal case, then score all climbers int target = n * m - 1; int count = 0; long long int best = MAX_DISTANCE; for (unsigned int i = 0; i < unique_costs.size(); ++i) { long long int score = find_shortest_path(target, unique_costs[i], graph); //DBG(score, "vs", best, "count=", count, "cost=", unique_costs[i].up, unique_costs[i].down, "repeats=", repeats[i]) if (score == best) { count += repeats[i]; } if (score < best) { best = score; count = repeats[i]; } auto stop_time = chrono::high_resolution_clock::now(); auto elapsed = chrono::duration_cast<std::chrono::milliseconds>(stop_time - start_time).count(); if (elapsed > 6500) { break; } } cout << best << " " << count << 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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 | /* * Copyright (C) 2020 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 <iostream> #include <string> #include <algorithm> #include <vector> #include <deque> #include <chrono> #include <unordered_map> using namespace std; #ifdef DEBUG template<typename... ArgTypes> inline void debug_print(ArgTypes... args) { using expand = int[]; (void)expand{0, ((cerr << args << " "), void(), 0)... }; cerr << endl; } #define DBG(...) debug_print(__VA_ARGS__); #define DBGx(x) cerr << #x << " " << x << endl; #define DBGa(array) cerr << #array << " "; for (auto a: array) { cerr << a << " "; } cerr << endl; #else #define DBG(...) #define DBGx(x) #define DBGa(array) #endif #define MAX_COST 1000000000 #define MAX_DISTANCE 4000000000000000 struct Cost { int up; int down; int operator<(const Cost& other) const { if (up == other.up) { return down < other.down; } else { return up < other.up; } } bool operator==(const Cost& other) const { return up == other.up && down == other.down; } }; struct Neighbour { int dx; int dy; }; const Neighbour NEIGHBOURHOOD[] = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}}; long long int find_shortest_path(int target, const Cost& cost, const vector<deque<int>>& graph) { vector<long long int> distances(target + 1, -1); distances[0] = 0; deque<pair<int, int>> queue; queue.push_back(make_pair(0, 0)); while (!queue.empty()) { int current = queue.front().first; queue.pop_front(); if (current == target) { continue; } for (auto node: graph[current]) { int weight = node > current ? cost.up : cost.down; long long int d = distances[current] + weight; //DBG("next=", node, " d=", d, "current=", current) if (distances[node] < 0) { distances[node] = d; queue.push_back(make_pair(node, d)); } else if (d < distances[node] + weight) { distances[node] = d; } } sort(queue.begin(), queue.end(), [](pair<int,int> a, pair<int,int> b){ return a.second < b.second; }); } return distances[target]; } int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int n, m, k; string row; int cost_up, cost_down; vector<string> map; vector<Cost> costs; cin >> n >> m >> k; map.reserve(n); costs.reserve(k); for (int i = 0; i < n; ++i) { cin >> row; map.emplace_back(row); } for (int i = 0; i < k; ++i) { cin >> cost_up >> cost_down; costs.push_back({cost_up, cost_down}); } auto start_time = chrono::high_resolution_clock::now(); // construct a graph (list of neighbours) vector<deque<int>> graph(n * m); for (int r = 0; r < n; ++r) { for (int c = 0; c < m; ++c) { if (map[r][c] == 'X') { continue; } int node = r * m + c; for (auto next: NEIGHBOURHOOD) { int x = c + next.dx; int y = r + next.dy; if (0 <= x && x < m && 0 <= y && y < n && map[y][x] != 'X') { graph[node].push_back(y * m + x); } } } } vector<Cost> unique_costs; vector<int> repeats; stable_sort(costs.begin(), costs.end()); for (auto cost: costs) { int index = unique_costs.size() - 1; if (!unique_costs.empty() && unique_costs[index] == cost) { repeats[index] += 1; } else { unique_costs.push_back(cost); repeats.push_back(1); } } // version A: for each climber run full dijkstra // version B: find 3 paths: for 2 divergent low,high and high,low // and 1 equal case, then score all climbers int target = n * m - 1; int count = 0; long long int best = MAX_DISTANCE; for (unsigned int i = 0; i < unique_costs.size(); ++i) { long long int score = find_shortest_path(target, unique_costs[i], graph); //DBG(score, "vs", best, "count=", count, "cost=", unique_costs[i].up, unique_costs[i].down, "repeats=", repeats[i]) if (score == best) { count += repeats[i]; } if (score < best) { best = score; count = repeats[i]; } auto stop_time = chrono::high_resolution_clock::now(); auto elapsed = chrono::duration_cast<std::chrono::milliseconds>(stop_time - start_time).count(); if (elapsed > 6500) { break; } } cout << best << " " << count << endl; return 0; } |