codevs6582 最大团

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define rp(i,x,y) for(register ll i=x;i<=y;++i)
#define lowbit(x) x&(-x)

ll n,m,zt[60],dp[68000000],sz[68000000];

inline ll read()
{
    register char ch=getchar();register ll x=0;register bool y=1;
    while(ch!=‘-‘ && (ch>‘9‘ || ch<‘0‘))ch=getchar();
    if(ch==‘-‘)ch=getchar(),y=0;
    while(ch>=‘0‘ && ch<=‘9‘)x=(x<<1)+(x<<3)+(ch^‘0‘),ch=getchar();
    return y?x:-x;
}

int main()
{
    n=read();m=read();rp(i,1,n)zt[i]=(1<<n)-1;rp(i,1,m){ll t1=read(),t2=read();zt[t1]^=(1<<t2);zt[t2]^=(1<<t1);}
    rp(i,1,25)dp[1<<i]=1,sz[1<<i]=1;
    rp(i,2,(1<<26)-1)
    {
        ll tmp=i;
        while(tmp)
        {
            ll v=lowbit(tmp);tmp-=v;
            ll sz1=sz[i^v]+1,nm1=dp[i^v];if(sz1>sz[i])sz[i]=sz1;if(sz1==sz[i])dp[i]+=nm1;
            ll sz2=sz[(i^v)&zt[v]],nm2=dp[(i^v)&zt[v]];if(sz2>sz[i])sz[i]=sz2;if(sz2==sz[i])dp[i]+=nm2;
        }
    }
    //预处理完毕?
    return 0;
}