我想在c中实现维基百科给出的*算法的伪代码,但我真的被困在了解什么是reconstruct_path函数,有人可以向我解释什么在这个函数中的变量(p ,p + current_node,set)表示?a *算法伪代码
function A*(start,goal)
closedset := the empty set // The set of nodes already evaluated.
openset := {start} // The set of tentative nodes to be evaluated, initially containing the start node
came_from := the empty map // The map of navigated nodes.
g_score[start] := 0 // Cost from start along best known path.
// Estimated total cost from start to goal through y.
f_score[start] := g_score[start] + heuristic_cost_estimate(start, goal)
while openset is not empty
current := the node in openset having the lowest f_score[] value
if current = goal
return reconstruct_path(came_from, goal)
remove current from openset
add current to closedset
for each neighbor in neighbor_nodes(current)
tentative_g_score := g_score[current] + dist_between(current,neighbor)
if neighbor in closedset
if tentative_g_score >= g_score[neighbor]
continue
if neighbor not in openset or tentative_g_score < g_score[neighbor]
came_from[neighbor] := current
g_score[neighbor] := tentative_g_score
f_score[neighbor] := g_score[neighbor] + heuristic_cost_estimate(neighbor, goal)
if neighbor not in openset
add neighbor to openset
return failure
function reconstruct_path(came_from, current_node)
if came_from[current_node] in set
p := reconstruct_path(came_from, came_from[current_node])
return (p + current_node)
else
return current_node
谢谢
非常感谢您的回答,我还有一个问题:如果设置了came_from [current_node],行中设置了什么? – user2102173 2013-03-02 18:53:01
我认为它检查结束条件,因为它是一个递归函数。我认为语义是“是否came_from [current_node]是列表中的最后一个节点?” – Heisenbug 2013-03-02 19:00:36
谢谢,但是提到的是什么列表:openset或者closedset或者其他什么? – user2102173 2013-03-02 19:06:18