mirror of
https://github.com/mfocko/blog.git
synced 2024-11-25 22:31:56 +01:00
108 lines
2.6 KiB
C++
108 lines
2.6 KiB
C++
#ifndef _GRAPH_HPP
|
||
#define _GRAPH_HPP
|
||
|
||
#include <cmath>
|
||
#include <limits>
|
||
#include <ostream>
|
||
#include <utility>
|
||
#include <vector>
|
||
|
||
using vertex_t = std::pair<int, int>;
|
||
|
||
struct graph {
|
||
graph(const std::vector<std::vector<char>>& map)
|
||
: map(map),
|
||
_height(static_cast<int>(map.size())),
|
||
_width(map.empty() ? 0 : static_cast<int>(map[0].size())) {}
|
||
|
||
static auto unreachable() -> int { return UNREACHABLE; }
|
||
static auto normal_cost() -> int { return NORMAL_COST; }
|
||
static auto vortex_cost() -> int { return VORTEX_COST; }
|
||
|
||
auto cost(const vertex_t& u, const vertex_t& v) const -> int {
|
||
auto [ux, uy] = u;
|
||
auto [vx, vy] = v;
|
||
|
||
auto md = std::abs(ux - vx) + std::abs(uy - vy);
|
||
switch (md) {
|
||
// ‹u = v›; staying on the same cell
|
||
case 0:
|
||
return 0;
|
||
// ‹u› and ‹v› are neighbours
|
||
case 1:
|
||
break;
|
||
// ‹u› and ‹v› are not neighbouring cells
|
||
default:
|
||
return UNREACHABLE;
|
||
}
|
||
|
||
// boundary check
|
||
if (vy < 0 || vy >= _height || vx < 0 || vx >= _width) {
|
||
return UNREACHABLE;
|
||
}
|
||
|
||
switch (map[vy][vx]) {
|
||
case '#':
|
||
return UNREACHABLE;
|
||
case '*':
|
||
return VORTEX_COST;
|
||
default:
|
||
return NORMAL_COST;
|
||
}
|
||
}
|
||
|
||
auto width() const -> int { return _width; }
|
||
auto height() const -> int { return _height; }
|
||
auto has(const vertex_t& v) const -> bool {
|
||
auto [x, y] = v;
|
||
return (0 <= y && y < _height) && (0 <= x && x < _width);
|
||
}
|
||
|
||
friend std::ostream& operator<<(std::ostream& os, const graph& g);
|
||
|
||
private:
|
||
std::vector<std::vector<char>> map;
|
||
int _height, _width;
|
||
|
||
const static int UNREACHABLE = std::numeric_limits<int>::max();
|
||
// XXX: modify here to change the price of entering the vortex
|
||
const static int VORTEX_COST = 5;
|
||
const static int NORMAL_COST = 1;
|
||
};
|
||
|
||
std::ostream& operator<<(std::ostream& os, const graph& g) {
|
||
for (const auto& row : g.map) {
|
||
for (const char cell : row) {
|
||
os << cell;
|
||
}
|
||
os << "\n";
|
||
}
|
||
|
||
return os;
|
||
}
|
||
|
||
const static std::vector<vertex_t> DIRECTIONS =
|
||
std::vector{std::make_pair(0, 1), std::make_pair(0, -1),
|
||
std::make_pair(1, 0), std::make_pair(-1, 0)};
|
||
|
||
using pqueue_item_t = std::pair<int, vertex_t>;
|
||
using pqueue_t = std::vector<pqueue_item_t>;
|
||
|
||
auto pushq(pqueue_t& q, pqueue_item_t v) -> void {
|
||
q.push_back(v);
|
||
std::push_heap(q.begin(), q.end(), std::greater<>{});
|
||
}
|
||
|
||
auto popq(pqueue_t& q) -> std::optional<pqueue_item_t> {
|
||
if (q.empty()) {
|
||
return {};
|
||
}
|
||
|
||
std::pop_heap(q.begin(), q.end(), std::greater<>{});
|
||
pqueue_item_t top = q.back();
|
||
q.pop_back();
|
||
|
||
return std::make_optional(top);
|
||
}
|
||
|
||
#endif /* _GRAPH_HPP */
|