Distance Code

#!/usr/bin/python3

import sys

do = int(sys.stdin.readline())
n = int(sys.stdin.readline())

graph = {}
visited = []


def findParent(cur_node, left_to_walk):
    #print("now checking node", cur_node, "left to walk", left_to_walk)

    visited.append(cur_node)
    if left_to_walk == 1:
        if len(graph[cur_node])<3:
            #print("node has space", len(graph[cur_node]))
            if cur_node == 1 and len(graph[cur_node]) > 1:
                return -1
            else:
                return cur_node
        else: return -1
    else:
        children = graph[cur_node]
        for c in children:
            if c not in visited:
                return findParent(c, left_to_walk -1)


if do == 1:
    edges = {}
    cur = [[] for i in range(0, n+1)]
    left = [i for i in range(1, n+1)]
    removed = []

    root_node = -1

    for i in range(n-1):
        a, b = [int(x) for x in sys.stdin.readline().split(" ")]
        if a not in edges:
            edges[a] = []
        if b not in edges:
            edges[b] = []
        edges[a].append(b)
        edges[b].append(a)
        cur[a].append(b)
        cur[b].append(a)

    if n == 2:
        print("2 1")
        sys.exit()

    for node in range(1, n+1):
        if len(cur[node]) == 2:
            root_node = node
            break
    # left to add condition for when is just 2 nodes

    while len(left) > 1:
        for i in range(1, n+1):
            if len(cur[i]) == 1 and i != root_node:
                cur[cur[i][0]].remove(i)
                removed.append(i)
                left.remove(i)
                cur[i] = []
    removed.append(left[0])
    print(" ".join([str(x) for x in removed]))

elif do == 2:
    code = [int(x) for x in sys.stdin.readline().split(" ")]
    code.reverse()

    if n == 2:
        print("2 1")
        sys.exit()
    #edges = {}
    #graph = [[] for i in range(0, n+1)]
    placed = [1, 2]
    graph[1] = [2]
    graph[2] = [1]
    last = 2

    left = [i for i in range(3, n+1)]
    for i in range(3, n+1):
        to_walk = code[i-2]
        #find a parent
        visited = []
        #a = findParent(last, to_walk)
        #finding the runtime error
        a = 1
        #print("found parent", a)
        if i not in graph:
            graph[i] = []
        graph[i].append(a)
        graph[a].append(i)

        placed.append(i)

        last = i

    done = []
    for i in range(1, n+1):
        for c in graph[i]:
            if c not in done:
                print(i, c)
        done.append(i)
    #print(graph)
sys.exit()

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 1, 2, 3

Verdict: ACCEPTED

Test 3

Group: 1, 2, 3

Verdict: WRONG ANSWER

Test 4

Group: 1, 2, 3

Verdict: ACCEPTED

Test 5

Group: 1, 2, 3

Verdict: WRONG ANSWER

Test 6

Group: 1, 2, 3

Verdict: WRONG ANSWER

Test 7

Group: 1, 2, 3

Verdict: ACCEPTED

Test 8

Group: 1, 2, 3

Verdict: ACCEPTED

Test 9

Group: 1, 2, 3

Verdict: WRONG ANSWER

Test 10

Group: 1, 2, 3

Verdict: WRONG ANSWER

Test 11

Group: 1, 2, 3

Verdict: WRONG ANSWER

Test 12

Group: 2, 3

Verdict: ACCEPTED

Test 13

Group: 2, 3

Verdict: WRONG ANSWER

Test 14

Group: 2, 3

Verdict: WRONG ANSWER

Test 15

Group: 2, 3

Verdict: WRONG ANSWER

Test 16

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 17

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 18

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 19

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 20

Group: 1, 2, 3

Verdict: WRONG ANSWER