장기판에 상놓기 - 가지수

#include <iostream>
#include <fstream>
#include <string>
using namespace std;
ifstream fin("input.txt");
ofstream fout("output.txt");
int chky[8]={2,3,3,2,-2,-3,-3,-2};
int chkx[8]={3,2,-2,-3,-3,-2,2,3};
int chkt[8][8]={0};
int cnt=0,row,col;

void janggi(int p,int k){
	if(p>=row){
		cnt++;
	}
	else{
		for(int i=0;i<col;i++){
			int flag=1;
			if(chkt[p][i])
				flag=0;
			if(flag){
				for(int j=0;j<8;j++){
					if(p+chkx[j]>=0 && p+chkx[j]< row && i+chky[j]>=0 && i+chky[j]< col)
						if(chkt[p+chkx[j]][i+chky[j]]==0)
							chkt[p+chkx[j]][i+chky[j]]=p+1;
				}
				janggi(p+1,i);
				for(j=0;j<8;j++){
					if(p+chkx[j]>=0 && p+chkx[j]< row && i+chky[j]>=0 && i+chky[j]< col)
						if(chkt[p+chkx[j]][i+chky[j]]==p+1)
							chkt[p+chkx[j]][i+chky[j]]=0;
				}
			}
		}
	}
}
void main(){
	fin >> row >> col;
	janggi(0,0);
	fout << cnt;
}