Snakeless path

sys.setrecursionlimit(1 << 20)
class Graph:
    def __init__(self, nodes):
        self.nodes = nodes
        self.graph = {node: [] for node in nodes}

    def add_edge(self, a, b):
        self.graph[a].append(b)
        self.graph[b].append(a)
    def remove_edge(self, a, b):
        self.graph[a].remove(b)
        self.graph[b].remove(a)
    def bfs_path(self, start, end):
        queue = [start]
        visited = {start}
        parent = {start: None}
        idx = 0
        while idx < len(queue):
            node = queue[idx]
            idx += 1
            if node == end:
                path = []
                while node is not None:
                    path.append(node)
                    node = parent[node]
                return path[::-1]
            for neighbor in self.graph[node]:
                if neighbor not in visited:
                    visited.add(neighbor)
                    parent[neighbor] = node
                    queue.append(neighbor)
        return None
n, m = map(int, input().split())
nodes = list(range(1, n + 1))
g = Graph(nodes)
for i in range(1, n + 1):
    for j in range(i + 1, n + 1):
        g.add_edge(i, j)
for i in range(m):
    a, b = map(int, input().split())
    g.remove_edge(a, b)
path = g.bfs_path(1, n)
if path is None:
    print(0)
else:
    print(len(path))
    print(' '.join(map(str, path)))

Test 1

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 2

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 3

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 4

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 5

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 6

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 7

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 8

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 9

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 10

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 11

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 12

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 13

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 14

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 15

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 16

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 17

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 18

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 19

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 20

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 21

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 22

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 23

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 24

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 25

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 26

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 27

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 28

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 29

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 30

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 31

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 32

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 33

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 34

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 35

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 36

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 37

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 38

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 39

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 40

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 41

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 42

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 43

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 44

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 45

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 46

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 47

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 48

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 49

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 50

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 51

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 52

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 53

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 54

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 55

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 56

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 57

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 58

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 59

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 60

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 61

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 62

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 63

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 64

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 65

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 66

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 67

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 68

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 69

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 70

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 71

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 72

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 73

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 74

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 75

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 76

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 77

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 78

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 79

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 80

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 81

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 82

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 83

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 84

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 85

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 86

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 87

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 88

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?

Test 89

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 1, in <module>
    sys.setrecursionlimit(1 << 20)
NameError: name 'sys' is not defined. Did you mean: abs?