浙大acm中1002题目请教

# include # define _clr(aa) (memset(aa,0,sizeof(aa))) using namespace std; int n,a[20],ans; bool check(int ch,int &b) { int i,j,c,z; for(i=1,b=0;i<=n;i++) { for(j=(i-1)*n+1,c=z=0;j<=i*n;j++) { if( ch & (1<<j) ) c++; i