本文共 2691 字，大约阅读时间需要 8 分钟。

????????????????????????????????????????????????????????????????????????k??????????????????

????

????

import sysfrom collections import dequedef main():    n, m, k, r = map(int, sys.stdin.readline().split())    nodes = []    for _ in range(n):        x, y = map(int, sys.stdin.readline().split())        nodes.append((x, y))    new_nodes = []    for _ in range(m):        x, y = map(int, sys.stdin.readline().split())        new_nodes.append((x, y))        # Encode all nodes    all_nodes = nodes + new_nodes    node_pos = [ (x,y) for (x,y) in all_nodes ]    node_id = [i for i in range(len(all_nodes))]    target_pos = node_pos[1]  # node 1 is the second router    # Create adjacency list    adj = [[] for _ in range(len(all_nodes))]    for i in range(len(all_nodes)):        for j in range(i+1, len(all_nodes)):            x1, y1 = node_pos[i]                x2, y2 = node_pos[j]                dx = x1 - x2                dy = y1 - y2                dist = dx*dx + dy*dy                if dist <= r*r:                    adj[i].append(j)                    adj[j].append(i)        # BFS setup    INF = float('inf')    distance = [ [INF]*(k+1) for _ in range(len(all_nodes)) ]    start_pos = node_id[0]  # position of first router    distance[start_pos][0] = 0    queue = deque()    queue.append( (start_pos, 0) )    found = False    min_trans = INF    while queue:        pos, added = queue.popleft()        if pos == node_id[1]:  # reached the second router            if added <=k:                if distance[pos][added] < min_trans:                    min_trans = distance[pos][added]                    found = True            continue        if distance[pos][added] >= INF:            continue        for neighbor in adj[pos]:            if neighbor < n:  # original node                new_added = added            else:  # new node                if added >= k:                    continue                new_added = added + 1            new_dist = distance[pos][added] + 1            if new_dist < distance[neighbor][new_added]:                distance[neighbor][new_added] = new_dist                queue.append( (neighbor, new_added) )        print(min_trans if found else -1)if __name__ == "__main__":    main()

????

??????????????????????????????????????????????????????

转载地址：http://wubx.baihongyu.com/