結果

問題 No.273 回文分解
ユーザー lam6er
提出日時 2025-03-31 17:20:33
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 43 ms / 2,000 ms
コード長 1,402 bytes
コンパイル時間 162 ms
コンパイル使用メモリ 82,712 KB
実行使用メモリ 60,072 KB
最終ジャッジ日時 2025-03-31 17:21:03
合計ジャッジ時間 2,592 ms
ジャッジサーバーID
(参考情報)
judge3 / judge5
このコードへのチャレンジ
(要ログイン)
ファイルパターン 結果
sample AC * 3
other AC * 32
権限があれば一括ダウンロードができます

ソースコード

diff #

s = input().strip()
n = len(s)

if n < 2:
    print(1)
    exit()

# Precompute palindrome table
pal = [[False] * n for _ in range(n)]
for i in range(n - 1, -1, -1):
    for j in range(i, n):
        if i == j:
            pal[i][j] = True
        elif j == i + 1:
            pal[i][j] = (s[i] == s[j])
        else:
            pal[i][j] = (s[i] == s[j]) and pal[i + 1][j - 1]

# Initialize dp arrays
dp0 = [-1] * (n + 1)  # dp0[i] represents the case where the first i characters form a palindrome without splitting
dp1 = [-1] * (n + 1)  # dp1[i] represents the case where at least one split is made

dp0[0] = 0  # Base case: zero characters

# Fill dp0: check if the substring from 0 to i-1 is a palindrome
for i in range(1, n + 1):
    if pal[0][i - 1]:
        dp0[i] = i
    else:
        dp0[i] = -1

# Fill dp1
for i in range(1, n + 1):
    max_val = -1
    for j in range(1, i):  # j ranges from 1 to i-1 to split into two non-empty parts
        if pal[j][i - 1]:
            current_max = -1
            if dp0[j] != -1:
                current_max = max(dp0[j], i - j)
            if dp1[j] != -1:
                candidate = max(dp1[j], i - j)
                if candidate > current_max:
                    current_max = candidate
            if current_max != -1 and current_max > max_val:
                max_val = current_max
    dp1[i] = max_val

print(dp1[n] if dp1[n] != -1 else 0)
0