Submission #2780481

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Source Code Expand

H, W = map(int, input().split())
C = [list(map(int, input().split())) for i in range(H)]
R = [[0] * W for i in range(H)]

# 白チョコを反転
for i in range(H):
    for j in range(W):
        if (i+j) % 2 == 0:
            R[i][j] = C[i][j]
        else:
            R[i][j] = -C[i][j]

# 2次元累積和を計算
for i in range(1, H):
    R[i][0] += R[i-1][0]
for i in range(1, W):
    R[0][i] += R[0][i-1]
for i in range(1, H):
    for j in range(1, W):
        R[i][j] = R[i][j] + R[i-1][j] + R[i][j-1] - R[i-1][j-1]

# out of index 対策
for i in range(H):
    R[i].insert(0, 0)
R.insert(0, [0] * (W+1))


# 答えを計算
ans = 0
for i in range(1, H+1):  # 上
    for j in range(1, W+1):  # 左
        for k in range(i, H+1):  # 下
            for l in range(j, W+1):  # 右
                if R[k][l] - R[i-1][l] - R[k][j-1] + R[i-1][j-1] == 0:
                    ans = max(ans, (k-i+1) * (l-j+1))

print(ans)

Submission Info

Judge Result