CTRICK - Card Trick
The magician shuffles a small pack of cards, holds it face down and performs the following procedure:
- The top card is moved to the bottom of the pack. The new top card is dealt face up onto the table. It is the Ace of Spades.
- Two cards are moved one at a time from the top to the bottom. The next card is dealt face up onto the table. It is the Two of Spades.
- Three cards are moved one at a time…
- This goes on until the nth and last card turns out to be the n of Spades.
This impressive trick works if the magician knows how to arrange the cards beforehand (and knows how to give a false shuffle). Your program has to determine the initial order of the cards for a given number of cards, 1 ≤ n ≤ 20000.
On the first line of the input is a single positive integer, telling the number of test cases to follow. Each case consists of one line containing the integer n.
For each test case, output a line with the correct permutation of the values 1 to n, space separated. The first number showing the top card of the pack, etc…
Input: 2 4 5 Output: 2 1 4 3 3 1 4 5 2
i think this a very good problem if you use treap, then it will be easier to implement :)
easy on paper,,implementation was slightly tough
n=1 ans=1 got 1 WA for this..But undoubtedly one of the best problems on BIT..!!
The constraints of n are wrong, it gets bigger than 20000. It costed me a wa (not a sigsev somehow xD)
BIT to the rescue _/\_
easy one with vector
Bit + binary search = AC ;)
a tough one with BITLast edit: 2016-12-12 20:46:52
got AC using BIT, now trying Segment Tree and getting TLE. Complexity of my solution using segment tree is O(n*logn) and with BIT it is O(n*logn*logn) with different constant factors, so segment tree should be performing better in time, am I missing something? Kindly help me on this.
For those who couldn't understand the problem, see this : https://www.youtube.com/watch?v=kP7FJGzorpI