changyuheng's blog

Python on contest #137 (problem #222) B
By changyuheng, 12 years ago, In English

Here is my code for 222 B


table = []

n, m, k = map(int, raw_input().split())

[table.append(raw_input().split()) for i in xrange(n)]

rs, cs = [i for i in xrange(n)], [i for i in xrange(m)]

for i in xrange(k):

    s, x, y = raw_input().split()

    x, y = int(x) - 1, int(y) - 1

    if s == "c":

        buf = cs[x]

        cs[x] = cs[y]

        cs[y] = buf

    elif s == "r":

        buf = rs[x]

        rs[x] = rs[y]

        rs[y] = buf

    else:

        print table[rs[x]][cs[y]]

It exceeded the time limit. I do not see any solution written in Python so come here for help. Could somebody give me an advise?

UPDATE: Thanks everybody. I just upload another solution in which replace the swap by buffer with by xor swap algorithm. It passed with 80ms under the time bound.

And I just saw that dkirienko submitted another solution with the a, b = b, a swap mechanism of Python. It speeds up a bit more.

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Comments Comments (2)
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12 years ago, # |
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its mayb because of Large input data set. Python's IO is too slow.

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12 years ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it

You can slightly optimize your program if you will use tuples instead of temporary variable buf to swap two elements of list:

cs[x], cs[y] = cs[y], cs[x]

Its enough for this problem. See submision 2128261

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