Buggy python submission (verdict: Runtime Error):
import sys
sys.setrecursionlimit(10**7)

N, M = map(int, input().split())
link = [[] for _ in range(N)]
for _ in range(M):
    a, b, c = map(int, input().split())
    link[a-1].append([b-1, c])
visited = [0] * N
ans = 0

#全ての頂点からループしてないか確かめるといけないかな？
def dfs(v, cnt):
    global ans
    if v == N-1:
        if visited[v] == 0:
            ans = cnt
        else:
            ans = max(ans, cnt)
        for p in link[v]:
            if visited[p[0]] and ans > 0:
                ans = 'inf'
                print(ans)
                exit()
            elif visited[p[0]] and ans <= 0:
                break
    visited[v] = 1
    for nv in link[v]:
        dfs(nv[0], cnt+nv[1])
    return

dfs(0, 0)
print(ans)


Fixed submission:
N, M = map(int, input().split())
a = [0] * M
b = [0] * M
c = [0] * M
for i in range(M):
    a[i], b[i], c[i] = map(int, input().split())
    c[i] = -c[i]
    
INF = 10 ** 13
dist = [INF] * N

dist[0] = 0

for loop in range(N-1):
    for i in range(M):
        if dist[a[i]-1] == INF:
            continue
        if dist[b[i]-1] > dist[a[i]-1] + c[i]:
            dist[b[i]-1] = dist[a[i]-1] + c[i]

ans = dist[N-1]

nega = [0] * N

for loop in range(N):
    for i in range(M):
        if dist[a[i]-1] == INF:
            continue
        if dist[b[i]-1] > dist[a[i]-1] + c[i]:
            dist[b[i]-1] = dist[a[i]-1] + c[i]
            nega[b[i]-1] = 1
        if nega[a[i]-1] == 1:
            nega[b[i]-1] = 1

if nega[N-1]:
    print('inf')
else:
    print(-ans)

Buggy python submission (verdict: Runtime Error):
import sys
sys.setrecursionlimit(10**12)

N, M = map(int, input().split())
link = [[] for _ in range(N)]
for _ in range(M):
    a, b, c = map(int, input().split())
    link[a-1].append([b-1, c])
visited = [0] * N
ans = 0

#全ての頂点からループしてないか確かめるといけないかな？
def dfs(v, cnt):
    global ans
    if v == N-1:
        if visited[v] == 0:
            ans = cnt
        else:
            ans = max(ans, cnt)
        for p in link[v]:
            if visited[p[0]] and ans > 0:
                ans = 'inf'
                print(ans)
                exit()
            elif visited[p[0]] and ans <= 0:
                break
    visited[v] = 1
    for nv in link[v]:
        dfs(nv[0], cnt+nv[1])
    return

dfs(0, 0)
print(ans)


Fixed submission:
N, M = map(int, input().split())
a = [0] * M
b = [0] * M
c = [0] * M
for i in range(M):
    a[i], b[i], c[i] = map(int, input().split())
    c[i] = -c[i]
    
INF = 10 ** 13
dist = [INF] * N

dist[0] = 0

for loop in range(N-1):
    for i in range(M):
        if dist[a[i]-1] == INF:
            continue
        if dist[b[i]-1] > dist[a[i]-1] + c[i]:
            dist[b[i]-1] = dist[a[i]-1] + c[i]

ans = dist[N-1]

nega = [0] * N

for loop in range(N):
    for i in range(M):
        if dist[a[i]-1] == INF:
            continue
        if dist[b[i]-1] > dist[a[i]-1] + c[i]:
            dist[b[i]-1] = dist[a[i]-1] + c[i]
            nega[b[i]-1] = 1
        if nega[a[i]-1] == 1:
            nega[b[i]-1] = 1

if nega[N-1]:
    print('inf')
else:
    print(-ans)

Buggy python submission (verdict: Runtime Error):
import sys
sys.setrecursionlimit(10**9)

N, M = map(int, input().split())
link = [[] for _ in range(N)]
for _ in range(M):
    a, b, c = map(int, input().split())
    link[a-1].append([b-1, c])
visited = [0] * N
ans = 0

#全ての頂点からループしてないか確かめるといけないかな？
def dfs(v, cnt):
    global ans
    if v == N-1:
        if visited[v] == 0:
            ans = cnt
        else:
            ans = max(ans, cnt)
        for p in link[v]:
            if visited[p[0]] and ans > 0:
                ans = 'inf'
                print(ans)
                exit()
            elif visited[p[0]] and ans <= 0:
                break
    visited[v] = 1
    for nv in link[v]:
        dfs(nv[0], cnt+nv[1])
    return

dfs(0, 0)
print(ans)


Fixed submission:
N, M = map(int, input().split())
a = [0] * M
b = [0] * M
c = [0] * M
for i in range(M):
    a[i], b[i], c[i] = map(int, input().split())
    c[i] = -c[i]
    
INF = 10 ** 13
dist = [INF] * N

dist[0] = 0

for loop in range(N-1):
    for i in range(M):
        if dist[a[i]-1] == INF:
            continue
        if dist[b[i]-1] > dist[a[i]-1] + c[i]:
            dist[b[i]-1] = dist[a[i]-1] + c[i]

ans = dist[N-1]

nega = [0] * N

for loop in range(N):
    for i in range(M):
        if dist[a[i]-1] == INF:
            continue
        if dist[b[i]-1] > dist[a[i]-1] + c[i]:
            dist[b[i]-1] = dist[a[i]-1] + c[i]
            nega[b[i]-1] = 1
        if nega[a[i]-1] == 1:
            nega[b[i]-1] = 1

if nega[N-1]:
    print('inf')
else:
    print(-ans)

Buggy python submission (verdict: Runtime Error):
N, M = map(int, input().split())
a = [0] * 1000
b = [0] * 1000
c = [0] * 1000
for i in range(M):
    a[i], b[i], c[i] = map(int, input().split())
    c[i] = -c[i]
    
INF = 10 ** 10
dist = [INF] * 1000

dist[0] = 0

for loop in range(N-1):
    for i in range(M):
        if dist[a[i]-1] == INF:
            continue
        if dist[b[i]-1] > dist[a[i]-1] + c[i]:
            dist[b[i]-1] = dist[a[i]-1] + c[i]

ans = dist[N-1]

nega = [0] * 1000

for loop in range(N):
    for i in range(M):
        if dist[a[i]-1] == INF:
            continue
        if dist[b[i]-1] > dist[a[i]-1] + c[i]:
            dist[b[i]-1] = dist[a[i]-1] + c[i]
            nega[b[i]-1] = 1
        if nega[a[i]-1] == 1:
            nega[b[i]-1] = 1

if nega[N-1]:
    print('inf')
else:
    print(-ans)

Fixed submission:
N, M = map(int, input().split())
a = [0] * M
b = [0] * M
c = [0] * M
for i in range(M):
    a[i], b[i], c[i] = map(int, input().split())
    c[i] = -c[i]
    
INF = 10 ** 13
dist = [INF] * N

dist[0] = 0

for loop in range(N-1):
    for i in range(M):
        if dist[a[i]-1] == INF:
            continue
        if dist[b[i]-1] > dist[a[i]-1] + c[i]:
            dist[b[i]-1] = dist[a[i]-1] + c[i]

ans = dist[N-1]

nega = [0] * N

for loop in range(N):
    for i in range(M):
        if dist[a[i]-1] == INF:
            continue
        if dist[b[i]-1] > dist[a[i]-1] + c[i]:
            dist[b[i]-1] = dist[a[i]-1] + c[i]
            nega[b[i]-1] = 1
        if nega[a[i]-1] == 1:
            nega[b[i]-1] = 1

if nega[N-1]:
    print('inf')
else:
    print(-ans)

Buggy python submission (verdict: Runtime Error):
N, M = map(int, input().split())
a = [0] * N
b = [0] * N
c = [0] * N
for i in range(M):
    a[i], b[i], c[i] = map(int, input().split())
    c[i] = -c[i]
    
INF = 10 ** 10
dist = [INF] * N

dist[0] = 0

for loop in range(N-1):
    for i in range(M):
        if dist[a[i]-1] == INF:
            continue
        if dist[b[i]-1] > dist[a[i]-1] + c[i]:
            dist[b[i]-1] = dist[a[i]-1] + c[i]

ans = dist[N-1]

nega = [0] * N

for loop in range(N):
    for i in range(M):
        if dist[a[i]-1] == INF:
            continue
        if dist[b[i]-1] > dist[a[i]-1] + c[i]:
            dist[b[i]-1] = dist[a[i]-1] + c[i]
            nega[b[i]-1] = 1
        if nega[a[i]-1] == 1:
            nega[b[i]-1] = 1

if nega[N-1]:
    print('inf')
else:
    print(-ans)

Fixed submission:
N, M = map(int, input().split())
a = [0] * M
b = [0] * M
c = [0] * M
for i in range(M):
    a[i], b[i], c[i] = map(int, input().split())
    c[i] = -c[i]
    
INF = 10 ** 13
dist = [INF] * N

dist[0] = 0

for loop in range(N-1):
    for i in range(M):
        if dist[a[i]-1] == INF:
            continue
        if dist[b[i]-1] > dist[a[i]-1] + c[i]:
            dist[b[i]-1] = dist[a[i]-1] + c[i]

ans = dist[N-1]

nega = [0] * N

for loop in range(N):
    for i in range(M):
        if dist[a[i]-1] == INF:
            continue
        if dist[b[i]-1] > dist[a[i]-1] + c[i]:
            dist[b[i]-1] = dist[a[i]-1] + c[i]
            nega[b[i]-1] = 1
        if nega[a[i]-1] == 1:
            nega[b[i]-1] = 1

if nega[N-1]:
    print('inf')
else:
    print(-ans)

Buggy python submission (verdict: Runtime Error):
import sys
sys.setrecursionlimit(10**9)

N, M = map(int, input().split())
link = [[] for _ in range(N)]
for _ in range(M):
    a, b, c = map(int, input().split())
    link[a-1].append([b-1, c])
visited = [0] * N
ans = 0

def dfs(v, cnt):
    global ans
    if v == N-1:
        if visited[v] == 0:
            ans = cnt
        else:
            ans = max(ans, cnt)
        for p in link[v]:
            if visited[p[0]] and ans > 0:
                ans = 'inf'
                print(ans)
                exit()
            elif visited[p[0]] and ans <= 0:
                break
    visited[v] = 1
    for nv in link[v]:
        dfs(nv[0], cnt+nv[1])
    return

dfs(0, 0)
print(ans)


Fixed submission:
N, M = map(int, input().split())
a = [0] * M
b = [0] * M
c = [0] * M
for i in range(M):
    a[i], b[i], c[i] = map(int, input().split())
    c[i] = -c[i]
    
INF = 10 ** 13
dist = [INF] * N

dist[0] = 0

for loop in range(N-1):
    for i in range(M):
        if dist[a[i]-1] == INF:
            continue
        if dist[b[i]-1] > dist[a[i]-1] + c[i]:
            dist[b[i]-1] = dist[a[i]-1] + c[i]

ans = dist[N-1]

nega = [0] * N

for loop in range(N):
    for i in range(M):
        if dist[a[i]-1] == INF:
            continue
        if dist[b[i]-1] > dist[a[i]-1] + c[i]:
            dist[b[i]-1] = dist[a[i]-1] + c[i]
            nega[b[i]-1] = 1
        if nega[a[i]-1] == 1:
            nega[b[i]-1] = 1

if nega[N-1]:
    print('inf')
else:
    print(-ans)

Buggy python submission (verdict: Runtime Error):
import sys
sys.setrecursionlimit(10**6)

N, M = map(int, input().split())
link = [[] for _ in range(N)]
for _ in range(M):
    a, b, c = map(int, input().split())
    link[a-1].append([b-1, c])
visited = [0] * N
ans = 0

def dfs(v, cnt):
    global ans
    if v == N-1:
        if visited[v] == 0:
            ans = cnt
        else:
            ans = max(ans, cnt)
        for p in link[v]:
            if visited[p[0]] and ans > 0:
                ans = 'inf'
                print(ans)
                exit()
            elif visited[p[0]] and ans <= 0:
                break
    visited[v] = 1
    for nv in link[v]:
        dfs(nv[0], cnt+nv[1])
    return

dfs(0, 0)
print(ans)


Fixed submission:
N, M = map(int, input().split())
a = [0] * M
b = [0] * M
c = [0] * M
for i in range(M):
    a[i], b[i], c[i] = map(int, input().split())
    c[i] = -c[i]
    
INF = 10 ** 13
dist = [INF] * N

dist[0] = 0

for loop in range(N-1):
    for i in range(M):
        if dist[a[i]-1] == INF:
            continue
        if dist[b[i]-1] > dist[a[i]-1] + c[i]:
            dist[b[i]-1] = dist[a[i]-1] + c[i]

ans = dist[N-1]

nega = [0] * N

for loop in range(N):
    for i in range(M):
        if dist[a[i]-1] == INF:
            continue
        if dist[b[i]-1] > dist[a[i]-1] + c[i]:
            dist[b[i]-1] = dist[a[i]-1] + c[i]
            nega[b[i]-1] = 1
        if nega[a[i]-1] == 1:
            nega[b[i]-1] = 1

if nega[N-1]:
    print('inf')
else:
    print(-ans)