Buggy python submission (verdict: Time Limit Exceeded):
def z_algo(s):
    """https://www.youtube.com/watch?v=f6ct5PQHqM0
    """
    n = len(s)
    ret = [0] * n

    ref_frm, ref_tail = -1, -1  # 一番末尾まで探索したケースの起点と終点
    for frm in range(n):
        cont = max(0, min(ret[frm - ref_frm], ref_tail - frm)) if ~ref_frm else 0

        while (frm + cont < n) and (s[cont] == s[frm + cont]): cont += 1
        ret[frm] = cont
        if ref_tail < frm + cont:
            ref_tail = frm + cont
            ref_frm = frm
    return ret


def main():
    N = int(input())
    S = input()

    ret = 0
    t = ''
    for c in reversed(S):
        # zalgoは[0,i]の比較で
        # 先頭が固定されているので
        # 末尾から文字を増やしていくことで
        # 先頭をSの各文字にしている
        t = c + t
        lcp = z_algo(t)
        for diff, len_ in enumerate(lcp):
            ret = max(ret, min(diff, len_))
    print(ret)


if __name__ == '__main__':
    main()


Fixed submission:
n = int(input())
s = input()

dp = [[0] * (n + 1) for _ in range(n + 1)]

res = 0
for i in range(n - 1, -1, -1):
    for j in range(n - 1, i, -1):
        if s[i] == s[j]:
            dp[i][j] = dp[i + 1][j + 1] + 1
            # dp[i][j] = max(dp[i][j], dp[i + 1][j + 1] + 1)
        res = max(res, min(dp[i][j], j - i))
print(res)

Buggy python submission (verdict: Time Limit Exceeded):
def z_algo(s):
    """https://www.youtube.com/watch?v=f6ct5PQHqM0
    """
    n = len(s)
    ret = [0] * n

    ref_frm, ref_tail = -1, -1  # 一番末尾まで探索したケースの起点と終点
    for frm in range(n):
        cont = max(0, min(ret[frm - ref_frm], ref_tail - frm)) if ~ref_frm else 0

        while (frm + cont < n) and (s[cont] == s[frm + cont]): cont += 1
        ret[frm] = cont
        if ref_tail < frm + cont:
            ref_tail = frm + cont
            ref_frm = frm
    return ret


def main():
    N = int(input())
    S = input()

    ret = 0
    t = ''
    for c in reversed(S):
        # zalgoは[0,i]の比較で
        # 先頭が固定されているので
        # 末尾から文字を増やしていくことで
        # 先頭をSの各文字にしている
        t = c + t
        lcp = z_algo(t)
        for diff, len_ in enumerate(lcp):
            ret = max(ret, min(diff, len_))
    print(ret)


if __name__ == '__main__':
    main()


Fixed submission:
n = int(input())
s = input()

dp = [[0] * (n + 1) for _ in range(n + 1)]

res = 0
for i in range(n - 1, -1, -1):
    for j in range(n - 1, i, -1):
        if s[i] == s[j]:
            dp[i][j] = dp[i + 1][j + 1] + 1
            # dp[i][j] = max(dp[i][j], dp[i + 1][j + 1] + 1)
        res = max(res, min(dp[i][j], j - i))
print(res)

Buggy python submission (verdict: Time Limit Exceeded):
def z_algo(s: str) -> list:
    """LCP(0,i)のlist"""
    N = len(s)
    ret = [-1] * N
    ret[0] = N
    i, j = 1, 0
    while i < N:
        while i + j < N and s[j] == s[i + j]:
            j += 1
        ret[i] = j
        if j == 0:
            i += 1
            continue
        k = 1
        while i + k < N and k + ret[k] < j:
            ret[i + k] = ret[k]
            k += 1
        i += k
        j -= k
    return ret


def main():
    N = int(input())
    S = input()

    ret = 0
    t = ''
    for c in reversed(S):
        t = c + t
        lcp = z_algo(t)
        for diff, len_ in enumerate(lcp):
            ret = max(ret, min(diff, len_))
    print(ret)


if __name__ == '__main__':
    main()


Fixed submission:
n = int(input())
s = input()

dp = [[0] * (n + 1) for _ in range(n + 1)]

res = 0
for i in range(n - 1, -1, -1):
    for j in range(n - 1, i, -1):
        if s[i] == s[j]:
            dp[i][j] = dp[i + 1][j + 1] + 1
            # dp[i][j] = max(dp[i][j], dp[i + 1][j + 1] + 1)
        res = max(res, min(dp[i][j], j - i))
print(res)

Buggy python submission (verdict: Time Limit Exceeded):
# 解説

def main():
    N = int(input())
    s = input()

    dp = [[0] * N for _ in range(N)]
    ans = 0
    for i in range(N - 1, -1, -1):
        for j in range(N - 1, -1, -1):
            if s[i] == s[j]:
                if i + 1 < N and j + 1 < N:
                    dp[i][j] = min(dp[i + 1][j + 1] + 1, j - i)
                    ans = max(ans, dp[i][j])
                else:
                    dp[i][j] = 1
            else:
                dp[i][j] = 0
    print(ans)


if __name__ == '__main__':
    main()


Fixed submission:
n = int(input())
s = input()

dp = [[0] * (n + 1) for _ in range(n + 1)]

res = 0
for i in range(n - 1, -1, -1):
    for j in range(n - 1, i, -1):
        if s[i] == s[j]:
            dp[i][j] = dp[i + 1][j + 1] + 1
            # dp[i][j] = max(dp[i][j], dp[i + 1][j + 1] + 1)
        res = max(res, min(dp[i][j], j - i))
print(res)

Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())
s = input()

dp = [[0] * (n + 1) for _ in range(n + 1)]

res = 0
for i in range(n - 1, -1, -1):
    for j in range(n - 1, i, -1):
        if s[i] == s[j]:
            dp[i][j] = max(dp[i][j], dp[i + 1][j + 1] + 1)
        res = max(res, min(dp[i][j], j - i))
print(res)


Fixed submission:
n = int(input())
s = input()

dp = [[0] * (n + 1) for _ in range(n + 1)]

res = 0
for i in range(n - 1, -1, -1):
    for j in range(n - 1, i, -1):
        if s[i] == s[j]:
            dp[i][j] = dp[i + 1][j + 1] + 1
            # dp[i][j] = max(dp[i][j], dp[i + 1][j + 1] + 1)
        res = max(res, min(dp[i][j], j - i))
print(res)

Buggy python submission (verdict: Time Limit Exceeded):
from collections import defaultdict
import sys

input = sys.stdin.readline

n = int(input())
s = input()

d = defaultdict(list)

for i in range(n):
    for j in range(i + 1, min(n, i + n // 2) + 1):
        # [i, j)
        d[s[i:j]].append((i, j))

d = sorted(d.items(), key=lambda x: len(x[0]), reverse=True)

for s, lis in d:
    if len(lis) == 1:
        continue
    r = lis[0][1]
    l = lis[-1][0]
    if r <= l:
        print(len(s))
        exit()
print(0)

# print(*d, sep='\n')


Fixed submission:
n = int(input())
s = input()

dp = [[0] * (n + 1) for _ in range(n + 1)]

res = 0
for i in range(n - 1, -1, -1):
    for j in range(n - 1, i, -1):
        if s[i] == s[j]:
            dp[i][j] = dp[i + 1][j + 1] + 1
            # dp[i][j] = max(dp[i][j], dp[i + 1][j + 1] + 1)
        res = max(res, min(dp[i][j], j - i))
print(res)