Buggy python submission (verdict: Runtime Error):
import sys
from collections import deque
import copy
import math
def get_read_func(fileobject):
    if fileobject == None :
        return raw_input
    else:
        return fileobject.readline

def dfs(graph, nd, toprogy, is_visited):
    is_visited.add(nd)
    for adj in graph[nd]:
        if adj not in is_visited:
            dfs(graph, adj, toprogy, is_visited)

    toprogy.appendleft(nd)

def main():
    if len(sys.argv) > 1:
        f = open(sys.argv[1])
    else:
        f = None
    read_func = get_read_func(f);
    input_raw = read_func().strip().split()
    [N, M] = [int(input_raw[0]), int(input_raw[1])]
    graph = {}
    inv_graph = {}
    for i in range(1, N + 1):
        graph[i] = []
        inv_graph[i] = []

    for i in range(N - 1 + M):
        input_raw = read_func().strip().split()
        [a, b] = [int(input_raw[0]), int(input_raw[1])]
        graph[a].append(b)
        inv_graph[b].append(a)

    sys.setrecursionlimit(20000)
    toprogy = deque([])
    is_visited = set([])
    for i in range(1, N + 1):
        if i not in is_visited:
            dfs(graph, i, toprogy, is_visited)

    toprogical_order = {}
    for i in range(N):
        toprogical_order[toprogy[i]] = i + 1

    for i in range(1, N + 1):
        max_toprogy = 0
        true_parent = 0
        for pare in inv_graph[i]:
            if max_toprogy < toprogical_order[pare]:
                max_toprogy =toprogical_order[pare]
                true_parent = pare
        print true_parent

if __name__ == '__main__':
    main()


Fixed submission:
import sys
from collections import deque
import copy
import math
def get_read_func(fileobject):
    if fileobject == None :
        return raw_input
    else:
        return fileobject.readline

def dfs(graph, nd, toprogy, is_visited):
    is_visited.add(nd)
    for adj in graph[nd]:
        if adj not in is_visited:
            dfs(graph, adj, toprogy, is_visited)

    toprogy.appendleft(nd)

def main():
    if len(sys.argv) > 1:
        f = open(sys.argv[1])
    else:
        f = None
    read_func = get_read_func(f);
    input_raw = read_func().strip().split()
    [N, M] = [int(input_raw[0]), int(input_raw[1])]
    graph = {}
    inv_graph = {}
    for i in range(1, N + 1):
        graph[i] = []
        inv_graph[i] = []

    for i in range(N - 1 + M):
        input_raw = read_func().strip().split()
        [a, b] = [int(input_raw[0]), int(input_raw[1])]
        graph[a].append(b)
        inv_graph[b].append(a)

    sys.setrecursionlimit(200000)
    toprogy = deque([])
    is_visited = set([])
    for i in range(1, N + 1):
        if i not in is_visited:
            dfs(graph, i, toprogy, is_visited)

    toprogical_order = {}
    for i in range(N):
        toprogical_order[toprogy[i]] = i + 1

    for i in range(1, N + 1):
        max_toprogy = 0
        true_parent = 0
        for pare in inv_graph[i]:
            if pare not in toprogical_order:
                continue
            if max_toprogy < toprogical_order[pare]:
                max_toprogy =toprogical_order[pare]
                true_parent = pare
        print true_parent

if __name__ == '__main__':
    main()

Buggy python submission (verdict: Runtime Error):
import sys
from collections import deque
import copy
import math
def get_read_func(fileobject):
    if fileobject == None :
        return raw_input
    else:
        return fileobject.readline

def dfs(graph, nd, toprogy, is_visited):
    is_visited.add(nd)
    for adj in graph[nd]:
        if adj not in is_visited:
            dfs(graph, adj, toprogy, is_visited)

    toprogy.appendleft(nd)

def main():
    if len(sys.argv) > 1:
        f = open(sys.argv[1])
    else:
        f = None
    read_func = get_read_func(f);
    input_raw = read_func().strip().split()
    [N, M] = [int(input_raw[0]), int(input_raw[1])]
    graph = {}
    inv_graph = {}
    for i in range(1, N + 1):
        graph[i] = []
        inv_graph[i] = []

    for i in range(N - 1 + M):
        input_raw = read_func().strip().split()
        [a, b] = [int(input_raw[0]), int(input_raw[1])]
        graph[a].append(b)
        inv_graph[b].append(a)

    sys.setrecursionlimit(20000)
    toprogy = deque([])
    is_visited = set([])
    for i in range(1, N + 1):
        if i not in is_visited:
            dfs(graph, i, toprogy, is_visited)

    toprogical_order = {}
    for i in range(N):
        toprogical_order[toprogy[i]] = i + 1

    for i in range(1, N + 1):
        max_toprogy = 0
        true_parent = 0
        for pare in inv_graph[i]:
            if max_toprogy < toprogical_order[pare]:
                max_toprogy =toprogical_order[pare]
                true_parent = pare
        print true_parent

if __name__ == '__main__':
    main()


Fixed submission:
import sys
from collections import deque
import copy
import math
def get_read_func(fileobject):
    if fileobject == None :
        return raw_input
    else:
        return fileobject.readline

def dfs(graph, nd, toprogy, is_visited):
    is_visited.add(nd)
    for adj in graph[nd]:
        if adj not in is_visited:
            dfs(graph, adj, toprogy, is_visited)

    toprogy.appendleft(nd)

def main():
    if len(sys.argv) > 1:
        f = open(sys.argv[1])
    else:
        f = None
    read_func = get_read_func(f);
    input_raw = read_func().strip().split()
    [N, M] = [int(input_raw[0]), int(input_raw[1])]
    graph = {}
    inv_graph = {}
    for i in range(1, N + 1):
        graph[i] = []
        inv_graph[i] = []

    for i in range(N - 1 + M):
        input_raw = read_func().strip().split()
        [a, b] = [int(input_raw[0]), int(input_raw[1])]
        graph[a].append(b)
        inv_graph[b].append(a)

    sys.setrecursionlimit(200000)
    toprogy = deque([])
    is_visited = set([])
    for i in range(1, N + 1):
        if i not in is_visited:
            dfs(graph, i, toprogy, is_visited)

    toprogical_order = {}
    for i in range(N):
        toprogical_order[toprogy[i]] = i + 1

    for i in range(1, N + 1):
        max_toprogy = 0
        true_parent = 0
        for pare in inv_graph[i]:
            if pare not in toprogical_order:
                continue
            if max_toprogy < toprogical_order[pare]:
                max_toprogy =toprogical_order[pare]
                true_parent = pare
        print true_parent

if __name__ == '__main__':
    main()

Buggy python submission (verdict: Runtime Error):
import sys
from collections import deque
import copy
import math
def get_read_func(fileobject):
    if fileobject == None :
        return raw_input
    else:
        return fileobject.readline

def dfs(graph, nd, toprogy, is_visited):
    is_visited.add(nd)
    for adj in graph[nd]:
        if adj not in is_visited:
            dfs(graph, adj, toprogy, is_visited)

    toprogy.appendleft(nd)

def main():
    if len(sys.argv) > 1:
        f = open(sys.argv[1])
    else:
        f = None
    read_func = get_read_func(f);
    input_raw = read_func().strip().split()
    [N, M] = [int(input_raw[0]), int(input_raw[1])]
    graph = {}
    inv_graph = {}
    for i in range(1, N + 1):
        graph[i] = []
        inv_graph[i] = []

    for i in range(N - 1 + M):
        input_raw = read_func().strip().split()
        [a, b] = [int(input_raw[0]), int(input_raw[1])]
        graph[a].append(b)
        inv_graph[b].append(a)


    toprogy = deque([])
    is_visited = set([])
    for i in range(1, N + 1):
        if i not in is_visited:
            dfs(graph, i, toprogy, is_visited)

    toprogical_order = {}
    for i in range(N):
        toprogical_order[toprogy[i]] = i + 1

    for i in range(1, N + 1):
        max_toprogy = 0
        true_parent = 0
        for pare in inv_graph[i]:
            if max_toprogy < toprogical_order[pare]:
                max_toprogy =toprogical_order[pare]
                true_parent = pare
        print true_parent

if __name__ == '__main__':
    main()


Fixed submission:
import sys
from collections import deque
import copy
import math
def get_read_func(fileobject):
    if fileobject == None :
        return raw_input
    else:
        return fileobject.readline

def dfs(graph, nd, toprogy, is_visited):
    is_visited.add(nd)
    for adj in graph[nd]:
        if adj not in is_visited:
            dfs(graph, adj, toprogy, is_visited)

    toprogy.appendleft(nd)

def main():
    if len(sys.argv) > 1:
        f = open(sys.argv[1])
    else:
        f = None
    read_func = get_read_func(f);
    input_raw = read_func().strip().split()
    [N, M] = [int(input_raw[0]), int(input_raw[1])]
    graph = {}
    inv_graph = {}
    for i in range(1, N + 1):
        graph[i] = []
        inv_graph[i] = []

    for i in range(N - 1 + M):
        input_raw = read_func().strip().split()
        [a, b] = [int(input_raw[0]), int(input_raw[1])]
        graph[a].append(b)
        inv_graph[b].append(a)

    sys.setrecursionlimit(200000)
    toprogy = deque([])
    is_visited = set([])
    for i in range(1, N + 1):
        if i not in is_visited:
            dfs(graph, i, toprogy, is_visited)

    toprogical_order = {}
    for i in range(N):
        toprogical_order[toprogy[i]] = i + 1

    for i in range(1, N + 1):
        max_toprogy = 0
        true_parent = 0
        for pare in inv_graph[i]:
            if pare not in toprogical_order:
                continue
            if max_toprogy < toprogical_order[pare]:
                max_toprogy =toprogical_order[pare]
                true_parent = pare
        print true_parent

if __name__ == '__main__':
    main()