OJ-Problems-Source/HDOJ/5305_autoAC.cpp

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#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cstring>
#include<string>
using namespace std;
int ans;
int n,m;
int cnt[10];
struct node{
int x,y;
void in(){
scanf("%d%d",&x,&y);
if(x>y)swap(x,y);
cnt[x]++;
cnt[y]++;
}
friend bool operator < (node a,node b){
if(a.x==b.x)return a.y<b.y;
return a.x<b.x;
}
}p[30];
void dfs(int t,int on[],int off[]){
if(t==m){
ans++;
return ;
}
int x=p[t].x;
int y=p[t].y;
on[x]++ , on[y]++;
if(on[x]<=cnt[x]/2 && off[x]<=cnt[x]/2 && on[y]<=cnt[y]/2 && off[y]<=cnt[y]/2 ){
dfs(t+1,on,off);
}
on[x]-- , on[y]--;
off[x]++ , off[y]++;
if(on[x]<=cnt[x]/2 && off[x]<=cnt[x]/2 && on[y]<=cnt[y]/2 && off[y]<=cnt[y]/2 ){
dfs(t+1,on,off);
}
off[x]-- , off[y]-- ;
}
int main(){
int T;scanf("%d",&T);
while(T--){
scanf("%d%d",&n,&m);
int on[10];
int off[10];
memset(cnt,0,sizeof cnt);
memset(on,0,sizeof on);
memset(off,0,sizeof off);
for(int i=0;i<m;i++){
p[i].in();
}
bool ok=false;
for(int i=1;i<=n;i++){
if(cnt[i]&1){
ok=true;
break;
}
}
if(ok){
printf("0\n");
continue;
}
sort(p,p+m);
ans=0;
dfs(0,on,off);
printf("%d\n",ans);
}
return 0;
}