Buggy python submission (verdict: Time Limit Exceeded):
# -*- coding: utf-8 -*-

import sys

def input(): return sys.stdin.readline().strip()
def list2d(a, b, c): return [[c] * b for i in range(a)]
def list3d(a, b, c, d): return [[[d] * c for j in range(b)] for i in range(a)]
def list4d(a, b, c, d, e): return [[[[e] * d for j in range(c)] for j in range(b)] for i in range(a)]
def ceil(x, y=1): return int(-(-x // y))
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(N=None): return list(MAP()) if N is None else [INT() for i in range(N)]
def Yes(): print('Yes')
def No(): print('No')
def YES(): print('YES')
def NO(): print('NO')
sys.setrecursionlimit(10 ** 9)
INF = 10 ** 18
MOD = 10 ** 9 + 7

N, Z, W = MAP()
A = [W] + LIST()

memo = list3d(N+1, N+1, 2, -1)
def rec(cur, prev, turn):
    if cur == N:
        return abs(A[cur] - A[prev])
    if memo[cur][prev][turn] != -1:
        return memo[cur][prev][turn]
    
    if turn == 0:
        res = 0
        for nxt in range(cur+1, N+1):
            res = max(res, rec(nxt, cur, 1 - turn))
    else:
        res = INF
        for nxt in range(cur+1, N+1):
            res = min(res, rec(nxt, cur, 1 - turn))
    memo[cur][prev][turn] = res
    return res
print(rec(0, -1, 0))


Fixed submission:
# -*- coding: utf-8 -*-

"""
参考：https://kimiyuki.net/writeup/algo/atcoder/arc-085-d/
・ミニマックス法
・メモ化再帰
・先手と後手にそれぞれのメモを作る
"""

import sys
from collections import defaultdict

# 再帰呼び出しの回数制限(デフォルト1000)
sys.setrecursionlimit(10 ** 9)
 
N, Z, W = map(int, input().split())
aN = list(map(int, input().split()))

# 先手番用メモ[残り山札数][相手のスコア] = このルートでのmax
# 後手番用メモ[残り山札数][相手のスコア] = このルートでのmin
memo1 = [defaultdict(int) for _ in range(N+1)]
memo2 = [defaultdict(int) for _ in range(N+1)]

def dfs(turn, rest, x, y):
    if rest == 0:
        return abs(x - y)
    # 先手番
    if turn % 2 == 0:
        # 既に見た局面ならメモの内容を返す
        if memo1[rest][y]: 
            return memo1[rest][y]
        mx = -1
        for i in range(N-rest, N):
            x = aN[i]
            idx = i+1
            mx = max(dfs(turn+1, N-idx, x, y), mx)
        # ここより深い所を探し終わったので結果をメモする
        memo1[rest][y] = mx
        return mx
    # 後手番
    else:
        if memo2[rest][x]: 
            return memo2[rest][x]
        mn = float('inf')
        for i in range(N-rest, N):
            y = aN[i]
            idx = i+1
            mn = min(dfs(turn+1, N-idx, x, y), mn)
        memo2[rest][x] = mn
        return mn

print(dfs(0, N, Z, W))

Buggy python submission (verdict: Time Limit Exceeded):
# -*- coding: utf-8 -*-

import sys

def input(): return sys.stdin.readline().strip()
def list2d(a, b, c): return [[c] * b for i in range(a)]
def list3d(a, b, c, d): return [[[d] * c for j in range(b)] for i in range(a)]
def list4d(a, b, c, d, e): return [[[[e] * d for j in range(c)] for j in range(b)] for i in range(a)]
def ceil(x, y=1): return int(-(-x // y))
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(N=None): return list(MAP()) if N is None else [INT() for i in range(N)]
def Yes(): print('Yes')
def No(): print('No')
def YES(): print('YES')
def NO(): print('NO')
sys.setrecursionlimit(10 ** 9)
INF = 10 ** 18
MOD = 10 ** 9 + 7

N, Z, W = MAP()
A = [W] + LIST()

memo = list3d(N+1, N+1, 2, -1)
def rec(cur, prev, turn):
    if cur == N:
        return abs(A[cur] - A[prev])
    if memo[cur][prev][turn] != -1:
        return memo[cur][prev][turn]
    
    if turn == 0:
        res = 0
        for nxt in range(cur+1, N+1):
            res = max(res, rec(nxt, cur, 1 - turn))
    else:
        res = INF
        for nxt in range(cur+1, N+1):
            res = min(res, rec(nxt, cur, 1 - turn))
    memo[cur][prev][turn] = res
    return res
print(rec(0, -1, 0))


Fixed submission:
# -*- coding: utf-8 -*-

"""
参考：https://kimiyuki.net/writeup/algo/atcoder/arc-085-d/
・ミニマックス法
・メモ化再帰
・先手と後手にそれぞれのメモを作る
"""

import sys
from collections import defaultdict

# 再帰呼び出しの回数制限(デフォルト1000)
sys.setrecursionlimit(10 ** 9)
 
N, Z, W = map(int, input().split())
aN = list(map(int, input().split()))

# 先手番用メモ[残り山札数][相手のスコア] = このルートでのmax
# 後手番用メモ[残り山札数][相手のスコア] = このルートでのmin
memo1 = [defaultdict(int) for _ in range(N+1)]
memo2 = [defaultdict(int) for _ in range(N+1)]

def dfs(turn, rest, x, y):
    if rest == 0:
        return abs(x - y)
    # 先手番
    if turn % 2 == 0:
        # 既に見た局面ならメモの内容を返す
        if memo1[rest][y]: 
            return memo1[rest][y]
        mx = -1
        for i in range(N-rest, N):
            x = aN[i]
            idx = i+1
            mx = max(dfs(turn+1, N-idx, x, y), mx)
        # ここより深い所を探し終わったので結果をメモする
        memo1[rest][y] = mx
        return mx
    # 後手番
    else:
        if memo2[rest][x]: 
            return memo2[rest][x]
        mn = float('inf')
        for i in range(N-rest, N):
            y = aN[i]
            idx = i+1
            mn = min(dfs(turn+1, N-idx, x, y), mn)
        memo2[rest][x] = mn
        return mn

print(dfs(0, N, Z, W))

Buggy python submission (verdict: Time Limit Exceeded):
# -*- coding: utf-8 -*-

import sys

def input(): return sys.stdin.readline().strip()
def list2d(a, b, c): return [[c] * b for i in range(a)]
def list3d(a, b, c, d): return [[[d] * c for j in range(b)] for i in range(a)]
def list4d(a, b, c, d, e): return [[[[e] * d for j in range(c)] for j in range(b)] for i in range(a)]
def ceil(x, y=1): return int(-(-x // y))
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(N=None): return list(MAP()) if N is None else [INT() for i in range(N)]
def Yes(): print('Yes')
def No(): print('No')
def YES(): print('YES')
def NO(): print('NO')
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
MOD = 10 ** 9 + 7

N, _, W = MAP()
A = [W] + LIST()

# memo[i][j] := 先手が最後にi枚目、後手が最後にj枚目を取った状態
memo = list2d(N+1, N+1, None)
def rec(a, b):
    if memo[a][b] is not None:
        return memo[a][b]
    # 終了条件(どちらかが最後まで札を取った)
    if a == N or b == N:
        res = abs(A[a]-A[b])
        memo[a][b] = res
        return res
    nxt = max(a, b)
    turn = 0 if a < b else 1
    if turn % 2 == 0:
        res = -INF
        for i in range(nxt+1, N+1):
            res = max(res, rec(i, b))
    else:
        res = INF
        for i in range(nxt+1, N+1):
            res = min(res, rec(a, i))
    memo[a][b] = res
    return res

ans = rec(-1, 0)
print(ans)


Fixed submission:
# -*- coding: utf-8 -*-

"""
参考：https://kimiyuki.net/writeup/algo/atcoder/arc-085-d/
・ミニマックス法
・メモ化再帰
・先手と後手にそれぞれのメモを作る
"""

import sys
from collections import defaultdict

# 再帰呼び出しの回数制限(デフォルト1000)
sys.setrecursionlimit(10 ** 9)
 
N, Z, W = map(int, input().split())
aN = list(map(int, input().split()))

# 先手番用メモ[残り山札数][相手のスコア] = このルートでのmax
# 後手番用メモ[残り山札数][相手のスコア] = このルートでのmin
memo1 = [defaultdict(int) for _ in range(N+1)]
memo2 = [defaultdict(int) for _ in range(N+1)]

def dfs(turn, rest, x, y):
    if rest == 0:
        return abs(x - y)
    # 先手番
    if turn % 2 == 0:
        # 既に見た局面ならメモの内容を返す
        if memo1[rest][y]: 
            return memo1[rest][y]
        mx = -1
        for i in range(N-rest, N):
            x = aN[i]
            idx = i+1
            mx = max(dfs(turn+1, N-idx, x, y), mx)
        # ここより深い所を探し終わったので結果をメモする
        memo1[rest][y] = mx
        return mx
    # 後手番
    else:
        if memo2[rest][x]: 
            return memo2[rest][x]
        mn = float('inf')
        for i in range(N-rest, N):
            y = aN[i]
            idx = i+1
            mn = min(dfs(turn+1, N-idx, x, y), mn)
        memo2[rest][x] = mn
        return mn

print(dfs(0, N, Z, W))

Buggy python submission (verdict: Time Limit Exceeded):
# -*- coding: utf-8 -*-

import sys

def input(): return sys.stdin.readline().strip()
def list2d(a, b, c): return [[c] * b for i in range(a)]
def list3d(a, b, c, d): return [[[d] * c for j in range(b)] for i in range(a)]
def list4d(a, b, c, d, e): return [[[[e] * d for j in range(c)] for j in range(b)] for i in range(a)]
def ceil(x, y=1): return int(-(-x // y))
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(N=None): return list(MAP()) if N is None else [INT() for i in range(N)]
def Yes(): print('Yes')
def No(): print('No')
def YES(): print('YES')
def NO(): print('NO')
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
MOD = 10 ** 9 + 7

N, _, W = MAP()
A = [W] + LIST()

# memo[i][j] := 先手が最後にi枚目、後手が最後にj枚目を取った状態
memo = list2d(N+1, N+1, -INF)
def rec(a, b):
    if memo[a][b] != -INF:
        return memo[a][b]
    # 終了条件(どちらかが最後まで札を取った)
    if a == N or b == N:
        res = abs(A[a]-A[b])
        memo[a][b] = res
        return res
    nxt = max(a, b)
    turn = 0 if a < b else 1
    if turn % 2 == 0:
        res = -INF
        for i in range(nxt+1, N+1):
            res = max(res, rec(i, b))
    else:
        res = INF
        for i in range(nxt+1, N+1):
            res = min(res, rec(a, i))
    memo[a][b] = res
    return res

ans = rec(-1, 0)
print(ans)


Fixed submission:
# -*- coding: utf-8 -*-

"""
参考：https://kimiyuki.net/writeup/algo/atcoder/arc-085-d/
・ミニマックス法
・メモ化再帰
・先手と後手にそれぞれのメモを作る
"""

import sys
from collections import defaultdict

# 再帰呼び出しの回数制限(デフォルト1000)
sys.setrecursionlimit(10 ** 9)
 
N, Z, W = map(int, input().split())
aN = list(map(int, input().split()))

# 先手番用メモ[残り山札数][相手のスコア] = このルートでのmax
# 後手番用メモ[残り山札数][相手のスコア] = このルートでのmin
memo1 = [defaultdict(int) for _ in range(N+1)]
memo2 = [defaultdict(int) for _ in range(N+1)]

def dfs(turn, rest, x, y):
    if rest == 0:
        return abs(x - y)
    # 先手番
    if turn % 2 == 0:
        # 既に見た局面ならメモの内容を返す
        if memo1[rest][y]: 
            return memo1[rest][y]
        mx = -1
        for i in range(N-rest, N):
            x = aN[i]
            idx = i+1
            mx = max(dfs(turn+1, N-idx, x, y), mx)
        # ここより深い所を探し終わったので結果をメモする
        memo1[rest][y] = mx
        return mx
    # 後手番
    else:
        if memo2[rest][x]: 
            return memo2[rest][x]
        mn = float('inf')
        for i in range(N-rest, N):
            y = aN[i]
            idx = i+1
            mn = min(dfs(turn+1, N-idx, x, y), mn)
        memo2[rest][x] = mn
        return mn

print(dfs(0, N, Z, W))

Buggy python submission (verdict: Time Limit Exceeded):
# -*- coding: utf-8 -*-

import sys

def input(): return sys.stdin.readline().strip()
def list2d(a, b, c): return [[c] * b for i in range(a)]
def list3d(a, b, c, d): return [[[d] * c for j in range(b)] for i in range(a)]
def list4d(a, b, c, d, e): return [[[[e] * d for j in range(c)] for j in range(b)] for i in range(a)]
def ceil(x, y=1): return int(-(-x // y))
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(N=None): return list(MAP()) if N is None else [INT() for i in range(N)]
def Yes(): print('Yes')
def No(): print('No')
def YES(): print('YES')
def NO(): print('NO')
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
MOD = 10 ** 9 + 7

N, _, W = MAP()
A = [W] + LIST()

# memo[i][j][k] := iのターンで先手が最後にj枚目、後手が最後にk枚目を取った状態
memo = list3d(2, N+1, N+1, -INF)
def rec(turn, a, b):
    if memo[turn][a][b] != -INF:
        return memo[turn][a][b]
    # 終了条件(どちらかが最後まで札を取った)
    if a == N or b == N:
        res = abs(A[a]-A[b])
        memo[turn][a][b] = res
        return res
    nxt = max(a, b)
    if turn % 2 == 0:
        res = -INF
        for i in range(nxt+1, N+1):
            res = max(res, rec(1-turn, i, b))
    else:
        res = INF
        for i in range(nxt+1, N+1):
            res = min(res, rec(1-turn, a, i))
    memo[turn][a][b] = res
    return res

ans = rec(0, 0, 0)
print(ans)


Fixed submission:
# -*- coding: utf-8 -*-

"""
参考：https://kimiyuki.net/writeup/algo/atcoder/arc-085-d/
・ミニマックス法
・メモ化再帰
・先手と後手にそれぞれのメモを作る
"""

import sys
from collections import defaultdict

# 再帰呼び出しの回数制限(デフォルト1000)
sys.setrecursionlimit(10 ** 9)
 
N, Z, W = map(int, input().split())
aN = list(map(int, input().split()))

# 先手番用メモ[残り山札数][相手のスコア] = このルートでのmax
# 後手番用メモ[残り山札数][相手のスコア] = このルートでのmin
memo1 = [defaultdict(int) for _ in range(N+1)]
memo2 = [defaultdict(int) for _ in range(N+1)]

def dfs(turn, rest, x, y):
    if rest == 0:
        return abs(x - y)
    # 先手番
    if turn % 2 == 0:
        # 既に見た局面ならメモの内容を返す
        if memo1[rest][y]: 
            return memo1[rest][y]
        mx = -1
        for i in range(N-rest, N):
            x = aN[i]
            idx = i+1
            mx = max(dfs(turn+1, N-idx, x, y), mx)
        # ここより深い所を探し終わったので結果をメモする
        memo1[rest][y] = mx
        return mx
    # 後手番
    else:
        if memo2[rest][x]: 
            return memo2[rest][x]
        mn = float('inf')
        for i in range(N-rest, N):
            y = aN[i]
            idx = i+1
            mn = min(dfs(turn+1, N-idx, x, y), mn)
        memo2[rest][x] = mn
        return mn

print(dfs(0, N, Z, W))

Buggy python submission (verdict: Time Limit Exceeded):
# -*- coding: utf-8 -*-

import sys

def input(): return sys.stdin.readline().strip()
def list2d(a, b, c): return [[c] * b for i in range(a)]
def list3d(a, b, c, d): return [[[d] * c for j in range(b)] for i in range(a)]
def list4d(a, b, c, d, e): return [[[[e] * d for j in range(c)] for j in range(b)] for i in range(a)]
def ceil(x, y=1): return int(-(-x // y))
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(N=None): return list(MAP()) if N is None else [INT() for i in range(N)]
def Yes(): print('Yes')
def No(): print('No')
def YES(): print('YES')
def NO(): print('NO')
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
MOD = 10 ** 9 + 7

N, _, W = MAP()
A = [W] + LIST()

# memo[i][j][k] := iのターンで先手が最後にj枚目、後手が最後にk枚目を取った状態
memo = list3d(2, N+1, N+1, -INF)
def rec(turn, a, b):
    if memo[turn][a][b] != -INF:
        return memo[turn][a][b]
    # 終了条件(どちらかが最後まで札を取った)
    if a == N or b == N:
        res = abs(A[a]-A[b])
        memo[turn][a][b] = res
        return res
    nxt = max(a, b)
    if turn % 2 == 0:
        res = -INF
        for i in range(nxt+1, N+1):
            res = max(res, rec(1-turn, i, b))
    else:
        res = INF
        for i in range(nxt+1, N+1):
            res = min(res, rec(1-turn, a, i))
    memo[turn][a][b] = res
    return res

ans = rec(0, 0, 0)
print(ans)


Fixed submission:
# -*- coding: utf-8 -*-

"""
参考：https://kimiyuki.net/writeup/algo/atcoder/arc-085-d/
・ミニマックス法
・メモ化再帰
・先手と後手にそれぞれのメモを作る
"""

import sys
from collections import defaultdict

# 再帰呼び出しの回数制限(デフォルト1000)
sys.setrecursionlimit(10 ** 9)
 
N, Z, W = map(int, input().split())
aN = list(map(int, input().split()))

# 先手番用メモ[残り山札数][相手のスコア] = このルートでのmax
# 後手番用メモ[残り山札数][相手のスコア] = このルートでのmin
memo1 = [defaultdict(int) for _ in range(N+1)]
memo2 = [defaultdict(int) for _ in range(N+1)]

def dfs(turn, rest, x, y):
    if rest == 0:
        return abs(x - y)
    # 先手番
    if turn % 2 == 0:
        # 既に見た局面ならメモの内容を返す
        if memo1[rest][y]: 
            return memo1[rest][y]
        mx = -1
        for i in range(N-rest, N):
            x = aN[i]
            idx = i+1
            mx = max(dfs(turn+1, N-idx, x, y), mx)
        # ここより深い所を探し終わったので結果をメモする
        memo1[rest][y] = mx
        return mx
    # 後手番
    else:
        if memo2[rest][x]: 
            return memo2[rest][x]
        mn = float('inf')
        for i in range(N-rest, N):
            y = aN[i]
            idx = i+1
            mn = min(dfs(turn+1, N-idx, x, y), mn)
        memo2[rest][x] = mn
        return mn

print(dfs(0, N, Z, W))

Buggy python submission (verdict: Time Limit Exceeded):
# -*- coding: utf-8 -*-

"""
参考：https://kimiyuki.net/writeup/algo/atcoder/arc-085-d/
・ミニマックス法
・メモ化再帰
・先手と後手にそれぞれのメモを作る
"""

import sys
from collections import defaultdict

# 再帰呼び出しの回数制限(デフォルト1000)
sys.setrecursionlimit(10 ** 9)
 
N, Z, W = map(int, input().split())
aN = list(map(int, input().split()))

# 先手番用メモ[残り山札数][相手のスコア] = このルートでのmax
# 後手番用メモ[残り山札数][相手のスコア] = このルートでのmin
memo1 = [defaultdict(int) for _ in range(N+1)]
memo2 = [defaultdict(int) for _ in range(N+1)]

def dfs(turn, rest, x, y):
    if rest == 0:
        return abs(x - y)
    # 先手番
    if turn % 2 == 0:
        # 既に見た局面ならメモの内容を返す
        if memo1[rest][y]: 
            return memo1[rest][y]
        mx = -1
        for i in range(N-rest, N):
            x = aN[i]
            idx = i+1
            mx = max(dfs(turn+1, N-idx, x, y), mx)
        # ここより深い所を探し終わったので結果をメモする
        memo1[rest][y] = mx
        return mx
    # 後手番
    else:
        if memo2[rest][x]: 
            return memo2[rest][x]
        mn = float('inf')
        for i in range(N-rest, N):
            y = aN[i]
            idx = i+1
            mn = min(dfs(turn+1, N-idx, x, y), mn)
        memo2[rest][x] = mn
        return mn

print(dfs(0, N, Z, W))


Fixed submission:
# -*- coding: utf-8 -*-

"""
参考：https://kimiyuki.net/writeup/algo/atcoder/arc-085-d/
・ミニマックス法
・メモ化再帰
・先手と後手にそれぞれのメモを作る
"""

import sys
from collections import defaultdict

# 再帰呼び出しの回数制限(デフォルト1000)
sys.setrecursionlimit(10 ** 9)
 
N, Z, W = map(int, input().split())
aN = list(map(int, input().split()))

# 先手番用メモ[残り山札数][相手のスコア] = このルートでのmax
# 後手番用メモ[残り山札数][相手のスコア] = このルートでのmin
memo1 = [defaultdict(int) for _ in range(N+1)]
memo2 = [defaultdict(int) for _ in range(N+1)]

def dfs(turn, rest, x, y):
    if rest == 0:
        return abs(x - y)
    # 先手番
    if turn % 2 == 0:
        # 既に見た局面ならメモの内容を返す
        if memo1[rest][y]: 
            return memo1[rest][y]
        mx = -1
        for i in range(N-rest, N):
            x = aN[i]
            idx = i+1
            mx = max(dfs(turn+1, N-idx, x, y), mx)
        # ここより深い所を探し終わったので結果をメモする
        memo1[rest][y] = mx
        return mx
    # 後手番
    else:
        if memo2[rest][x]: 
            return memo2[rest][x]
        mn = float('inf')
        for i in range(N-rest, N):
            y = aN[i]
            idx = i+1
            mn = min(dfs(turn+1, N-idx, x, y), mn)
        memo2[rest][x] = mn
        return mn

print(dfs(0, N, Z, W))

Buggy python submission (verdict: Time Limit Exceeded):
# -*- coding: utf-8 -*-

import sys

# 再帰呼び出しの回数制限(デフォルト1000)
sys.setrecursionlimit(10 ** 9)
 
N, Z, W = map(int, input().split())
aN = list(map(int, input().split()))

def dfs(turn, rest, x, y):
    if rest == 0:
        return abs(x - y)
    if turn % 2 == 0:
        mx = -1
        for i in range(N-rest, N):
            x = aN[i]
            idx = i+1
            mx = max(dfs(turn+1, N-idx, x, y), mx)
        return mx
    else:
        mn = float('inf')
        for i in range(N-rest, N):
            y = aN[i]
            idx = i+1
            mn = min(dfs(turn+1, N-idx, x, y), mn)
        return mn

print(dfs(0, N, Z, W))


Fixed submission:
# -*- coding: utf-8 -*-

"""
参考：https://kimiyuki.net/writeup/algo/atcoder/arc-085-d/
・ミニマックス法
・メモ化再帰
・先手と後手にそれぞれのメモを作る
"""

import sys
from collections import defaultdict

# 再帰呼び出しの回数制限(デフォルト1000)
sys.setrecursionlimit(10 ** 9)
 
N, Z, W = map(int, input().split())
aN = list(map(int, input().split()))

# 先手番用メモ[残り山札数][相手のスコア] = このルートでのmax
# 後手番用メモ[残り山札数][相手のスコア] = このルートでのmin
memo1 = [defaultdict(int) for _ in range(N+1)]
memo2 = [defaultdict(int) for _ in range(N+1)]

def dfs(turn, rest, x, y):
    if rest == 0:
        return abs(x - y)
    # 先手番
    if turn % 2 == 0:
        # 既に見た局面ならメモの内容を返す
        if memo1[rest][y]: 
            return memo1[rest][y]
        mx = -1
        for i in range(N-rest, N):
            x = aN[i]
            idx = i+1
            mx = max(dfs(turn+1, N-idx, x, y), mx)
        # ここより深い所を探し終わったので結果をメモする
        memo1[rest][y] = mx
        return mx
    # 後手番
    else:
        if memo2[rest][x]: 
            return memo2[rest][x]
        mn = float('inf')
        for i in range(N-rest, N):
            y = aN[i]
            idx = i+1
            mn = min(dfs(turn+1, N-idx, x, y), mn)
        memo2[rest][x] = mn
        return mn

print(dfs(0, N, Z, W))

Buggy python submission (verdict: Runtime Error):
# -*- coding: utf-8 -*-

# 再帰呼び出しの回数制限(デフォルト1000)
sys.setrecursionlimit(10 ** 9)

N, Z, W = map(int, input().split())
aN = list(map(int, input().split()))

def dfs(turn, rest, x, y):
    if rest == 0:
        return abs(x - y)
    if turn % 2 == 0:
        mx = -1
        for i in range(N-rest, N):
            x = aN[i]
            idx = i+1
            mx = max(dfs(turn+1, N-idx, x, y), mx)
        return mx
    else:
        mn = float('inf')
        for i in range(N-rest, N):
            y = aN[i]
            idx = i+1
            mn = min(dfs(turn+1, N-idx, x, y), mn)
        return mn

print(dfs(0, N, Z, W))


Fixed submission:
# -*- coding: utf-8 -*-

"""
参考：https://kimiyuki.net/writeup/algo/atcoder/arc-085-d/
・ミニマックス法
・メモ化再帰
・先手と後手にそれぞれのメモを作る
"""

import sys
from collections import defaultdict

# 再帰呼び出しの回数制限(デフォルト1000)
sys.setrecursionlimit(10 ** 9)
 
N, Z, W = map(int, input().split())
aN = list(map(int, input().split()))

# 先手番用メモ[残り山札数][相手のスコア] = このルートでのmax
# 後手番用メモ[残り山札数][相手のスコア] = このルートでのmin
memo1 = [defaultdict(int) for _ in range(N+1)]
memo2 = [defaultdict(int) for _ in range(N+1)]

def dfs(turn, rest, x, y):
    if rest == 0:
        return abs(x - y)
    # 先手番
    if turn % 2 == 0:
        # 既に見た局面ならメモの内容を返す
        if memo1[rest][y]: 
            return memo1[rest][y]
        mx = -1
        for i in range(N-rest, N):
            x = aN[i]
            idx = i+1
            mx = max(dfs(turn+1, N-idx, x, y), mx)
        # ここより深い所を探し終わったので結果をメモする
        memo1[rest][y] = mx
        return mx
    # 後手番
    else:
        if memo2[rest][x]: 
            return memo2[rest][x]
        mn = float('inf')
        for i in range(N-rest, N):
            y = aN[i]
            idx = i+1
            mn = min(dfs(turn+1, N-idx, x, y), mn)
        memo2[rest][x] = mn
        return mn

print(dfs(0, N, Z, W))

Buggy python submission (verdict: Runtime Error):
# -*- coding: utf-8 -*-
 
N, Z, W = map(int, input().split())
aN = list(map(int, input().split()))

def dfs(turn, rest, x, y):
    if rest == 0:
        return abs(x - y)
    if turn % 2 == 0:
        mx = -1
        for i in range(N-rest, N):
            x = aN[i]
            idx = i+1
            mx = max(dfs(turn+1, N-idx, x, y), mx)
        return mx
    else:
        mn = float('inf')
        for i in range(N-rest, N):
            y = aN[i]
            idx = i+1
            mn = min(dfs(turn+1, N-idx, x, y), mn)
        return mn

print(dfs(0, N, Z, W))


Fixed submission:
# -*- coding: utf-8 -*-

"""
参考：https://kimiyuki.net/writeup/algo/atcoder/arc-085-d/
・ミニマックス法
・メモ化再帰
・先手と後手にそれぞれのメモを作る
"""

import sys
from collections import defaultdict

# 再帰呼び出しの回数制限(デフォルト1000)
sys.setrecursionlimit(10 ** 9)
 
N, Z, W = map(int, input().split())
aN = list(map(int, input().split()))

# 先手番用メモ[残り山札数][相手のスコア] = このルートでのmax
# 後手番用メモ[残り山札数][相手のスコア] = このルートでのmin
memo1 = [defaultdict(int) for _ in range(N+1)]
memo2 = [defaultdict(int) for _ in range(N+1)]

def dfs(turn, rest, x, y):
    if rest == 0:
        return abs(x - y)
    # 先手番
    if turn % 2 == 0:
        # 既に見た局面ならメモの内容を返す
        if memo1[rest][y]: 
            return memo1[rest][y]
        mx = -1
        for i in range(N-rest, N):
            x = aN[i]
            idx = i+1
            mx = max(dfs(turn+1, N-idx, x, y), mx)
        # ここより深い所を探し終わったので結果をメモする
        memo1[rest][y] = mx
        return mx
    # 後手番
    else:
        if memo2[rest][x]: 
            return memo2[rest][x]
        mn = float('inf')
        for i in range(N-rest, N):
            y = aN[i]
            idx = i+1
            mn = min(dfs(turn+1, N-idx, x, y), mn)
        memo2[rest][x] = mn
        return mn

print(dfs(0, N, Z, W))