Created
July 23, 2012 13:38
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N Kueen - HackerRank Code Sprint - Interviewstreet.com
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import java.util.ArrayList; | |
import java.util.Scanner; | |
public class NKueen { | |
private static ArrayList<Integer> kueens = new ArrayList<Integer>(); | |
static int N = 0; | |
public static void main (String args[]){ | |
Scanner in = new Scanner(System.in); | |
//input | |
N = in.nextInt(); | |
//loop through | |
generatePositions(); | |
//output positions | |
outputKueenPositions(); | |
} | |
private static void outputKueenPositions() { | |
System.out.println(N); | |
for(int i = 0; i < kueens.size();i++){ | |
if(i == kueens.size() -1){ | |
System.out.print(kueens.get(i) + " "); | |
}else{ | |
System.out.print(kueens.get(i) + " "); | |
} | |
} | |
} | |
private static void generatePositions() { | |
boolean col1Empty = true; | |
boolean col2Empty = true; | |
int c = 3; //column number - start from column 3 | |
if(N <= 3){ | |
c = 1; | |
kueens.add(c); | |
}else{ | |
kueens.add(c); | |
for(int r = 1; r < N;r++){ | |
if(c+3 <= N){ | |
c = c+3; | |
kueens.add(c); | |
}else{ | |
if(col1Empty){ | |
c = 1; | |
col1Empty = false; | |
kueens.add(c); | |
}else if(col2Empty){ | |
c = 2; | |
col2Empty = false; | |
kueens.add(c); | |
}else{ | |
c = (c+3) - N; | |
kueens.add(c); | |
} | |
} | |
} | |
} | |
} | |
} |
Yeah, it was a very basic attempt, I still haven't come up with any correct solution. The only pattern I could see was each queen was separated by 3 columns and 1 row, and no matter what N is, there will be 3 diagonal rows of Queens...
I need more practice :D
If it makes you feel better, we didn't get it either.
Write out the numbers row-by-row. What do you notice about them? You
already mentioned a pattern; see if you can write it out. It's a simple
formula.
Hint (rot13): Vg vaibyirf n zbqhyhf.
- Christian
…On Mon, Jul 23, 2012 at 5:08 PM, robbio87 < ***@***.*** > wrote:
Yeah, it was a very basic attempt, I still haven't come up with any
correct solution. The only pattern I could see was each queen was separated
by 3 columns and 1 row, and no matter what N is, there will be 3 diagonal
rows of Queens...
I need more practice :D
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I'm impressed that you got to 100! My friends and I only got to 25-30 in the allotted time. The people who got 10,000 didn't use any kind of "traditional" approach like backtracking. Look at the given solution to 10x10. Can you see a pattern? Try generalizing that to 10^k x 10^k.