67 lines
1.7 KiB
Go
67 lines
1.7 KiB
Go
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package solver
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import (
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"maze-solver/maze"
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"maze-solver/utils"
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"sort"
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)
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type AStarSolver struct {
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dist_from_start map[*maze.Node]int
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dist_from_end map[*maze.Node]int
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parent map[*maze.Node]*maze.Node
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stack sorted_stack
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}
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func (s *AStarSolver) Solve(m *maze.Maze) *maze.SolvedMaze {
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defer utils.Timer("A* algorithm", 2)()
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s.dist_from_start = make(map[*maze.Node]int, len(m.Nodes))
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s.dist_from_end = make(map[*maze.Node]int, len(m.Nodes))
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s.parent = make(map[*maze.Node]*maze.Node, len(m.Nodes))
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current, end := m.Nodes[0], m.Nodes[len(m.Nodes)-1]
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for _, node := range m.Nodes {
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s.dist_from_start[node] = 0
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s.dist_from_end[node] = int(node.Coords.Distance(end.Coords))
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}
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for current != end {
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current.Visited = true
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for _, child := range []*maze.Node{current.Left, current.Right, current.Up, current.Down} {
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if child != nil {
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dist := s.dist_from_start[current] + int(current.Coords.Distance(child.Coords))
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if !child.Visited {
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s.parent[child] = current
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s.dist_from_start[child] = dist
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s.stack.insert(child, &s.dist_from_end)
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} else if s.dist_from_start[child] > dist {
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s.parent[child] = current
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s.dist_from_start[child] = dist
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sort.Slice(s.stack, func(i, j int) bool {
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return s.dist_from_end[s.stack[i]] < s.dist_from_end[s.stack[j]]
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})
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}
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}
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}
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current = s.stack.pop()
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}
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solution := make([]*maze.Node, 0, len(m.Nodes))
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for current != m.Nodes[0] {
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solution = append(solution, current)
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current = s.parent[current]
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}
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solution = append(solution, m.Nodes[0])
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for i, j := 0, len(solution)-1; i < j; i, j = i+1, j-1 {
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solution[i], solution[j] = solution[j], solution[i]
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}
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return &maze.SolvedMaze{
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Maze: m,
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Solution: solution,
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}
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}
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