Buggy python submission (verdict: Runtime Error):
N, M = map(int, input().split())
 
G = [[] for _ in range(N + 1)]
for i in range(M):
    x, y = map(int, input().split())
    G[x] += [y]
# print(G)
 
dp = [-1] * (N + 1)
 
 
def func(n):
    if dp[n] != -1:
        return dp[n]
    cnt = 0
	# 先にノードが存在する場合
	# ノードが存在しない場合は、cnt=0のままforをすっ飛ばす
    for m in G[n]:
        cnt = max(cnt, func(m) + 1)
    dp[n] = cnt
    return cnt
 
 
for i in range(1, N + 1):
    func(i)
 
# print(dp)
print(max(dp))

Fixed submission:
import sys
sys.setrecursionlimit(10**9)
 
 
N, M = map(int, input().split())
 
G = [[] for _ in range(N + 1)]
for i in range(M):
    x, y = map(int, input().split())
    G[x] += [y]
# print(G)
 
dp = [-1] * (N + 1)
 
 
def func(n):
    if dp[n] != -1:
        return dp[n]
    cnt = 0
	# 先にノードが存在する場合
	# ノードが存在しない場合は、cnt=0のままforをすっ飛ばす
    for m in G[n]:
        cnt = max(cnt, func(m) + 1)
    dp[n] = cnt
    return cnt
 
 
for i in range(1, N + 1):
    func(i)
 
# print(dp)
print(max(dp))

Buggy python submission (verdict: Runtime Error):
N, M = map(int, input().split())
 
G = [[] for _ in range(N + 1)]
for i in range(M):
    x, y = map(int, input().split())
    G[x] += [y]
# print(G)
 
dp = [-1] * (N + 1)
 
 
def func(n):
    if dp[n] != -1:
        return dp[n]
    cnt = 0
	# 先にノードが存在する場合
	# ノードが存在しない場合は、cnt=0のままforをすっ飛ばす
    for m in G[n]:
        cnt = max(cnt, func(m) + 1)
    dp[n] = cnt
    return cnt
 
 
for i in range(1, N + 1):
    func(i)
 # print(dp)
print(max(dp))

Fixed submission:
import sys
sys.setrecursionlimit(10**9)
 
 
N, M = map(int, input().split())
 
G = [[] for _ in range(N + 1)]
for i in range(M):
    x, y = map(int, input().split())
    G[x] += [y]
# print(G)
 
dp = [-1] * (N + 1)
 
 
def func(n):
    if dp[n] != -1:
        return dp[n]
    cnt = 0
	# 先にノードが存在する場合
	# ノードが存在しない場合は、cnt=0のままforをすっ飛ばす
    for m in G[n]:
        cnt = max(cnt, func(m) + 1)
    dp[n] = cnt
    return cnt
 
 
for i in range(1, N + 1):
    func(i)
 
# print(dp)
print(max(dp))

Buggy python submission (verdict: Runtime Error):
N,M = map(int, input().split())
edge=[[] for j in range(N+1)]
x = [0] * M
y = [0] * M

#N,M=4,5
#x=[1, 1, 3, 2, 3]
#y=[2, 3, 2, 4, 4]
#edge=[[], [2, 3], [4], [2, 4], []]  

for i in range(M):
    x[i], y[i] = map(int, input().split())
    edge[x[i]].append(y[i])
dp=[-1]*(N+1)
def f(x):
    if dp[x]!=-1:
        return dp[x]
    num=0
   
    for i in edge[x]:
        num=max(num,f(i)+1)
    
    dp[x]=num
    return dp[x]
m=0
for i in range(1,N+1):
    m=max(m,f(i))
print(m)


Fixed submission:
import sys
sys.setrecursionlimit(10**9)
 
 
N, M = map(int, input().split())
 
G = [[] for _ in range(N + 1)]
for i in range(M):
    x, y = map(int, input().split())
    G[x] += [y]
# print(G)
 
dp = [-1] * (N + 1)
 
 
def func(n):
    if dp[n] != -1:
        return dp[n]
    cnt = 0
	# 先にノードが存在する場合
	# ノードが存在しない場合は、cnt=0のままforをすっ飛ばす
    for m in G[n]:
        cnt = max(cnt, func(m) + 1)
    dp[n] = cnt
    return cnt
 
 
for i in range(1, N + 1):
    func(i)
 
# print(dp)
print(max(dp))

Buggy python submission (verdict: Runtime Error):
N,M = map(int, input().split())
edge=[[] for j in range(N+1)]
x = [0] * M
y = [0] * M

#N,M=4,5
#x=[1, 1, 3, 2, 3]
#y=[2, 3, 2, 4, 4]
#edge=[[], [2, 3], [4], [2, 4], []]  

for i in range(M):
    x[i], y[i] = map(int, input().split())
    edge[x[i]].append(y[i])
dp=[-1]*(N+1)
def f(x):
    if dp[x]!=-1:
        return dp[x]
    num=0
   
    for i in edge[x]:
        num=max(num,f(i)+1)
    
    dp[x]=num
    return dp[x]
for i in range(1,N+1):
    i,f(i)
print(max(dp))

Fixed submission:
import sys
sys.setrecursionlimit(10**9)
 
 
N, M = map(int, input().split())
 
G = [[] for _ in range(N + 1)]
for i in range(M):
    x, y = map(int, input().split())
    G[x] += [y]
# print(G)
 
dp = [-1] * (N + 1)
 
 
def func(n):
    if dp[n] != -1:
        return dp[n]
    cnt = 0
	# 先にノードが存在する場合
	# ノードが存在しない場合は、cnt=0のままforをすっ飛ばす
    for m in G[n]:
        cnt = max(cnt, func(m) + 1)
    dp[n] = cnt
    return cnt
 
 
for i in range(1, N + 1):
    func(i)
 
# print(dp)
print(max(dp))

Buggy python submission (verdict: Runtime Error):
N,M = map(int, input().split())
edge=[[] for j in range(N+1)]
x = [0] * M
y = [0] * M

#N,M=4,5
#x=[1, 1, 3, 2, 3]
#y=[2, 3, 2, 4, 4]
#edge=[[], [2, 3], [4], [2, 4], []]  

for i in range(M):
    x[i], y[i] = map(int, input().split())
    edge[x[i]].append(y[i])
dp=[0]*(N+1)
def f(x):
    if edge[x]==[]:
        return dp[x]
    #num=0
    if edge[x]!=[]:
        num=0
        for i in edge[x]:
            num=max(num,f(i)+1)
        #del edge[x][0]
        dp[x]=max(dp[x],num)
        dp[x]=num
        return dp[x]
for i in range(N):
    f(i+1)
print(max(dp))


Fixed submission:
import sys
sys.setrecursionlimit(10**9)
 
 
N, M = map(int, input().split())
 
G = [[] for _ in range(N + 1)]
for i in range(M):
    x, y = map(int, input().split())
    G[x] += [y]
# print(G)
 
dp = [-1] * (N + 1)
 
 
def func(n):
    if dp[n] != -1:
        return dp[n]
    cnt = 0
	# 先にノードが存在する場合
	# ノードが存在しない場合は、cnt=0のままforをすっ飛ばす
    for m in G[n]:
        cnt = max(cnt, func(m) + 1)
    dp[n] = cnt
    return cnt
 
 
for i in range(1, N + 1):
    func(i)
 
# print(dp)
print(max(dp))

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
N,M = map(int, input().split())
edge=[[] for j in range(N+1)]
x = [0] * M
y = [0] * M

#N,M=4,5
#x=[1, 1, 3, 2, 3]
#y=[2, 3, 2, 4, 4]
#edge=[[], [2, 3], [4], [2, 4], []]  

for i in range(M):
    x[i], y[i] = map(int, input().split())
    edge[x[i]].append(y[i])

def g(x):
    q=deque([x])
    move=[[1,0],[-1,0],[0,1],[0,-1]]
    num=-1
    s=False
    while q:
        #print(q)
        for i in range(len(q)):
            b=q.popleft()
            if edge[b]==[]:
                #print(num)
                #print(H*W-kuro-num-1)
                num=num
            else:
                for i in edge[b]:
                    q.append(i)
        num+=1
    return num        
m=0
for i in range(N):
    m=max(m,g(i+1))
print(m)

Fixed submission:
import sys
sys.setrecursionlimit(10**9)
 
 
N, M = map(int, input().split())
 
G = [[] for _ in range(N + 1)]
for i in range(M):
    x, y = map(int, input().split())
    G[x] += [y]
# print(G)
 
dp = [-1] * (N + 1)
 
 
def func(n):
    if dp[n] != -1:
        return dp[n]
    cnt = 0
	# 先にノードが存在する場合
	# ノードが存在しない場合は、cnt=0のままforをすっ飛ばす
    for m in G[n]:
        cnt = max(cnt, func(m) + 1)
    dp[n] = cnt
    return cnt
 
 
for i in range(1, N + 1):
    func(i)
 
# print(dp)
print(max(dp))