Buggy python submission (verdict: Time Limit Exceeded):
def main():
    s = input()
    t = input()
    ls = len(s)
    lt = len(t)
    dp = [[0] * (lt+1) for _ in range(ls+1)]

    for i in range(ls):
        for j in range(lt):
            if s[i] == t[j]:
                dp[i+1][j+1] = max(dp[i+1][j+1], dp[i][j]+1)
            dp[i+1][j+1] = max(dp[i+1][j+1], dp[i+1][j])
            dp[i+1][j+1] = max(dp[i+1][j+1], dp[i][j+1])

    #import numpy as np
    #print(np.array(dp))

    #from collections import deque
    #ans = deque()

    ans = ''
    i, j = ls, lt
    while i > 0 and j > 0:
        if dp[i][j] == dp[i-1][j]:
            i -= 1
        elif dp[i][j] == dp[i][j-1]:
            j -= 1
        else:
            i -= 1
            j -= 1
            #ans.appendleft(s[i])
            ans = s[i] + ans
    #print(''.join(ans))
    print(ans)
if __name__ == '__main__':
    main()

Fixed submission:
s = input()
t = input()
ls = len(s)
lt = len(t)
dp = [[0] * (lt+1) for _ in range(ls+1)]

for i in range(ls):
    for j in range(lt):
        if s[i] == t[j]:
            dp[i+1][j+1] = max(dp[i+1][j+1], dp[i][j]+1)
        dp[i+1][j+1] = max(dp[i+1][j+1], dp[i+1][j])
        dp[i+1][j+1] = max(dp[i+1][j+1], dp[i][j+1])

#import numpy as np
#print(np.array(dp))

#from collections import deque
#ans = deque()

ans = ''
i, j = ls, lt
while i > 0 and j > 0:
    if dp[i][j] == dp[i-1][j]:
        i -= 1
    elif dp[i][j] == dp[i][j-1]:
        j -= 1
    else:
        i -= 1
        j -= 1
        #ans.appendleft(s[i])
        ans = s[i] + ans
#print(''.join(ans))
print(ans)

Buggy python submission (verdict: Runtime Error):
s = input()
t = input()
ls = len(s)
lt = len(t)
dp = [[0] * (lt+1) for _ in range(ls+1)]

for i in range(ls):
    for j in range(lt):
        if s[i] == t[j]:
            dp[i+1][j+1] = max(dp[i+1][j+1], dp[i][j]+1)
        dp[i+1][j+1] = max(dp[i+1][j+1], dp[i+1][j])
        dp[i+1][j+1] = max(dp[i+1][j+1], dp[i][j+1])

#import numpy as np
#print(np.array(dp))

#from collections import deque
#ans = deque()

ans = []
i, j = ls, lt
while i > 0 and j > 0:
    if dp[i][j] == dp[i-1][j]:
        i -= 1
    elif dp[i][j] == dp[i][j-1]:
        j -= 1
    else:
        i -= 1
        j -= 1
        #ans.appendleft(s[i])
        ans = s[i] + ans
#print(''.join(ans))
print(ans)

Fixed submission:
s = input()
t = input()
ls = len(s)
lt = len(t)
dp = [[0] * (lt+1) for _ in range(ls+1)]

for i in range(ls):
    for j in range(lt):
        if s[i] == t[j]:
            dp[i+1][j+1] = max(dp[i+1][j+1], dp[i][j]+1)
        dp[i+1][j+1] = max(dp[i+1][j+1], dp[i+1][j])
        dp[i+1][j+1] = max(dp[i+1][j+1], dp[i][j+1])

#import numpy as np
#print(np.array(dp))

#from collections import deque
#ans = deque()

ans = ''
i, j = ls, lt
while i > 0 and j > 0:
    if dp[i][j] == dp[i-1][j]:
        i -= 1
    elif dp[i][j] == dp[i][j-1]:
        j -= 1
    else:
        i -= 1
        j -= 1
        #ans.appendleft(s[i])
        ans = s[i] + ans
#print(''.join(ans))
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
s = input()
t = input()
ls = len(s)
lt = len(t)
dp = [[0] * (lt+1) for _ in range(ls+1)]

for i in range(ls):
    for j in range(lt):
        if s[i] == t[j]:
            dp[i+1][j+1] = max(dp[i+1][j+1], dp[i][j]+1)
        dp[i+1][j+1] = max(dp[i+1][j+1], dp[i+1][j])
        dp[i+1][j+1] = max(dp[i+1][j+1], dp[i][j+1])

#import numpy as np
#print(np.array(dp))

from collections import deque
ans = deque()

#ans = []
i, j = ls, lt
while i > 0 and j > 0:
    if dp[i][j] == dp[i-1][j]:
        i -= 1
    elif dp[i][j] == dp[i][j-1]:
        j -= 1
    else:
        i -= 1
        j -= 1
        ans.appendleft(s[i])
        #ans = s[i] + ans
print(''.join(ans))

#print(ans)

Fixed submission:
s = input()
t = input()
ls = len(s)
lt = len(t)
dp = [[0] * (lt+1) for _ in range(ls+1)]

for i in range(ls):
    for j in range(lt):
        if s[i] == t[j]:
            dp[i+1][j+1] = max(dp[i+1][j+1], dp[i][j]+1)
        dp[i+1][j+1] = max(dp[i+1][j+1], dp[i+1][j])
        dp[i+1][j+1] = max(dp[i+1][j+1], dp[i][j+1])

#import numpy as np
#print(np.array(dp))

#from collections import deque
#ans = deque()

ans = ''
i, j = ls, lt
while i > 0 and j > 0:
    if dp[i][j] == dp[i-1][j]:
        i -= 1
    elif dp[i][j] == dp[i][j-1]:
        j -= 1
    else:
        i -= 1
        j -= 1
        #ans.appendleft(s[i])
        ans = s[i] + ans
#print(''.join(ans))
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
s = input()
t = input()
ls = len(s)
lt = len(t)
dp = [[0] * (lt+1) for _ in range(ls+1)]

for i in range(ls):
    for j in range(lt):
        if s[i] == t[j]:
            dp[i+1][j+1] = max(dp[i+1][j+1], dp[i][j]+1)
        dp[i+1][j+1] = max(dp[i+1][j+1], dp[i+1][j])
        dp[i+1][j+1] = max(dp[i+1][j+1], dp[i][j+1])

#import numpy as np
#print(np.array(dp))

ans = ''
i, j = ls, lt
while i > 0 and j > 0:
    if dp[i][j] == dp[i-1][j]:
        i -= 1
    elif dp[i][j] == dp[i][j-1]:
        j -= 1
    else:
        i -= 1
        j -= 1
        ans = s[i] + ans
print(ans)

Fixed submission:
s = input()
t = input()
ls = len(s)
lt = len(t)
dp = [[0] * (lt+1) for _ in range(ls+1)]

for i in range(ls):
    for j in range(lt):
        if s[i] == t[j]:
            dp[i+1][j+1] = max(dp[i+1][j+1], dp[i][j]+1)
        dp[i+1][j+1] = max(dp[i+1][j+1], dp[i+1][j])
        dp[i+1][j+1] = max(dp[i+1][j+1], dp[i][j+1])

#import numpy as np
#print(np.array(dp))

#from collections import deque
#ans = deque()

ans = ''
i, j = ls, lt
while i > 0 and j > 0:
    if dp[i][j] == dp[i-1][j]:
        i -= 1
    elif dp[i][j] == dp[i][j-1]:
        j -= 1
    else:
        i -= 1
        j -= 1
        #ans.appendleft(s[i])
        ans = s[i] + ans
#print(''.join(ans))
print(ans)