Problem p03108 (python)

Fixed submission:
import sys
sys.setrecursionlimit(100000)

N, M = map(int, input().split())
E = []
for i in range(M):
    a, b = map(int, input().split())
    E.append((a-1, b-1))

tree = {n: n for n in range(N)}
child = {n: 1 for n in range(N)}

max_connection = N*(N-1)//2


def find_head(i):
    if tree[i] != i:
        tree[i] = find_head(tree[i])
        return tree[i]
    else:
        return i


connection = 0
out_list = [max_connection]
for e in E[:0:-1]:
    head_e0 = find_head(e[0])
    head_e1 = find_head(e[1])

    if head_e0 == head_e1:
        out_list.append(max_connection-connection)
    else:
        tree[head_e1] = head_e0
        connection = connection + child[head_e0]*child[head_e1]
        child[head_e0] += child[head_e1]
        out_list.append(max_connection - connection)
    if max_connection == connection:
        break

if len(out_list) != M:
    out_list += [0]*(M-len(out_list))

for o in out_list[::-1]:
    print(o)

Buggy submission (verdict: Runtime Error):
import sys
sys.setrecursionlimit(10000)

N, M = map(int, input().split())
E = []
for i in range(M):
    a, b = map(int, input().split())
    E.append((a-1, b-1))

tree = {n: n for n in range(N)}
child = {n: 1 for n in range(N)}

max_connection = N*(N-1)//2


def find_head(i):
    if tree[i] != i:
        return find_head(tree[i])
    else:
        return i


connection = 0
out_list = [max_connection]
for e in E[:0:-1]:
    head_e0 = find_head(e[0])
    head_e1 = find_head(e[1])

    if head_e0 == head_e1:
        out_list.append(max_connection-connection)
    else:
        tree[head_e1] = head_e0
        connection = connection + child[head_e0]*child[head_e1]
        child[head_e0] += child[head_e1]
        out_list.append(max_connection - connection)
    if max_connection == connection:
        break

if len(out_list) != M:
    out_list += [0]*(M-len(out_list))

for o in out_list[::-1]:
    print(o)

Buggy submission (verdict: Runtime Error):
N, M = map(int, input().split())
E = []
for i in range(M):
    a, b = map(int, input().split())
    E.append((a-1, b-1))

tree = {n: n for n in range(N)}
child = {n: 1 for n in range(N)}

max_connection = N*(N-1)//2


def find_head(i):
    if tree[i] != i:
        return find_head(tree[i])
    else:
        return i


connection = 0
out_list = [max_connection]
for e in E[:0:-1]:
    head_e0 = find_head(e[0])
    head_e1 = find_head(e[1])

    if head_e0 == head_e1:
        out_list.append(max_connection-connection)
    else:
        tree[head_e1] = head_e0
        connection = connection + child[head_e0]*child[head_e1]
        child[head_e0] += child[head_e1]
        out_list.append(max_connection - connection)
    if max_connection == connection:
        break

if len(out_list) != M:
    out_list += [0]*(M-len(out_list))

for o in out_list[::-1]:
    print(o)

Buggy submission (verdict: Runtime Error):
N, M = map(int, input().split())
E = []
for i in range(M):
    a, b = map(int, input().split())
    E.append((a-1, b-1))

tree = {n: n for n in range(N)}
child = {n: 1 for n in range(N)}

max_connection = N*(N-1)//2


def find_head(i):
    if tree[i] != i:
        return find_head(tree[i])
    else:
        return i


connection = 0
out_list = [max_connection]
for e in E[:0:-1]:
    head_e0 = find_head(e[0])
    head_e1 = find_head(e[1])

    if head_e0 == head_e1:
        out_list.append(max_connection-connection)
    else:
        tree[head_e1] = head_e0
        connection = connection + child[head_e0]*child[head_e1]
        child[head_e0] += child[head_e1]
        out_list.append(max_connection - connection)

for o in out_list[::-1]:
    print(o)