""" とりあえずのナイーブ解放 全体を①惑星の訪問順を決める、②ステーションの配置を決めるの2つに分ける ①惑星の訪問順 - ランダムシャッフルで初期解を作る - 2点swap山登り ②ステーションの配置 - ①で決めた訪問順で実際に通る道からなる集合をつくる - その集合の中で長さ順にM個の枝を選び、その中点にステーションを配置する """ #from heapq import heappush,heappop from random import shuffle,sample N,M = map(int,input().split()) AB = [tuple(map(int,input().split())) for _ in range(N)] alpha = 5 G = [{} for _ in range(N)] for i in range(N-1): x1,y1 = AB[i] for j in range(i+1,N): x2,y2 = AB[j] dist = (x2-x1)**2 + (y2-y1)**2 dist *= alpha**2 G[i][j] = G[j][i] = dist # ダイクストラ(惑星専用) def dijkstra(start = 0, INF=10**20): from heapq import heappop, heappush d = [INF for i in range(len(G))] prev = [-1]*len(G) d[start] = 0 que = [] heappush(que, (0, start)) while que: d_, v = heappop(que) if d[v] < d_: continue for u, c in G[v].items(): if d[u] > d[v] + c: d[u] = d[v] + c prev[u] = v heappush(que, (d[u], u)) return d,prev # sからtまでの最短経路を復元 def recover_path(s,t): prev = PREV[s] path = [t] while prev[t] != -1: t = prev[t] path.append(t) return path[::-1] # 道順を与えられたときに距離を返す def calc_score(path): assert len(path) == N+1, "The length of path should be N+1" score = 0 for i in range(N): score += D[path[i]][path[i+1]] return score D = [[0]*N for _ in range(N)] PREV = [[-1]*N for _ in range(N)] for i in range(N): D[i],PREV[i] = dijkstra(i) ans = list(range(1,N)) score = calc_score([0]+ans+[0]) # 初期解 for i in range(100): ans2 = ans[:] shuffle(ans2) score2 = calc_score([0]+ans2+[0]) if score2 < score: score = score2 ans = ans2 #print(score) # 2点swapで山登り for itr in range(10**5): i,j = sample(range(N-1),2) ans[i],ans[j] = ans[j],ans[i] score2 = calc_score([0]+ans+[0]) if score2 < score: score = score2 else: ans[i],ans[j] = ans[j],ans[i] # ステーションを配置 # 使用する枝のうち長い方から順にM個の中点(だいたい)に置くだけ used = {} ans = [0]+ans+[0] all_path = [ans[0]] for i in range(N): s,t = ans[i],ans[i+1] path = recover_path(s,t) for j in range(len(path)-1): a = path[j] b = path[j+1] all_path.append(b) if a > b: a,b = b,a if (a,b) not in used: used[(a,b)] = 0 used[(a,b)] += 1 #print(used) pairs = list(used.keys()) dists = [D[i][j] for i,j in pairs] longestM = sorted(zip(dists,pairs),reverse=True)[:M] #print(longestM) # ステーションを配置 pos = {} for _, (i,j) in longestM: x1,y1 = AB[i] x2,y2 = AB[j] pos[(i,j)] = ((x1+x2)//2, (y1+y2)//2, len(pos)) #print(pos) #print(score) #print(all_path) ANS = [f"{1} {all_path[0]+1}"] for i in range(len(all_path)-1): a,b = all_path[i],all_path[i+1] x,y = a,b if x > y: x,y = y,x if (x,y) in pos: z = pos[(x,y)][-1] ANS.append(f"{2} {z+1}") ANS.append(f"{1} {b+1}") CD = [0]*M for c,d,z in pos.values(): CD[z] = (c,d) #print(score) for c,d in CD: print(c,d) print(len(ANS)) print("\n".join(ANS))