P1896 [SCOI2005] Non-aggression king

Title Description

Put K Kings in NxN's chessboard, so that they do not attack each other, there are many kinds of layout plan. The king can attack it up and down, as well as the left upper left lower right up to the bottom right in the next eight directions in the vicinity of a grid, a total of 8 squares.

Input/output format

Input format:

Only one row, containing two numbers n,k (1 <=n <=9, 0 <= K <= n * N)

Output format:

Number of programmes received

Input and Output Sample input example # #:

3 2

Sample # # of output:

16

Puzzle: State compression motion rules, with an integer binary representation of the Board on the case of a row, put the pawn is 1, not put as 0, you can preprocess all possible states, using a bitwise operation to determine whether two states can coexist in two adjacent rows. (The bit arithmetic is a bit blind).

#include <iostream>#include<cstdio>using namespacestd;intn,k,i,j,k1,all,f[9][ -][ +],cnt[ +],p;BOOLf1[ +],f2[ +][ +];Long Longans;voidxx () {intt,x;  for(; i<all;i++)        if((i& (i>>1))==0)        {             for(t=0, x=i;x;x/=2) t+=x&1; Cnt[i]=T; F1[i]=true; }     for(i=0; i<all;i++)      if(F1[i]) for(j=0; j<all;j++)          if(F1[j])if((i&j) = =0&& (i& (j>>1))==0&& (j& (i>>1))==0) F2[i][j]=true;}intMain () {scanf ("%d%d",&n,&k); if(K> (n+1)/2* (n+1)/2) {cout<<0<<Endl; return 0; } All=1<<N;    XX ();  for(i=0; i<all;i++) f[0][cnt[i]][i]=1;  for(i=1; i<n;i++)         for(j=0; j<all;j++)          if(F1[j]) for(k1=0; k1<all;k1++)                if(F2[j][k1]) for(P=cnt[j];p +cnt[k1]<=k;p++) F[i][p+cnt[k1]][k1]+=f[i-1][p][j];  for(i=0, n--;i<all;i++) ans+=F[n][k][i]; cout<<ans; return 0;}

pressure DP

P1896 [SCOI2005] Non-aggression king