愤怒的小鸟

题面

状压dp

#include<bits/stdc++.h>
using namespace std;
const double eps=1e-8;
int t,n,m,lines[20][20],lowunbit[1<<20],dp[1<<20];  
double x[20],y[20];
void equation(double &x,double &y,double a1,double b1,double c1,double a2,double b2,double c2){ 
    y=(a1*c2-a2*c1)/(a1*b2-a2*b1);
    x=(c1-b1*y)/a1;
}
int main(){
    for(int i=0;i<(1<<18);i++){ 
        int j=1;
        for(;j<=18 && i&(1<<(j-1));j++);
        lowunbit[i]=j;
    }
    scanf("%d",&t);
    while(t--){
        memset(lines,0,sizeof(lines));  
        memset(dp,0x3f,sizeof(dp));
        dp[0]=0;
        scanf("%d%d",&n,&m);
        for(int i=1;i<=n;i++) scanf("%lf%lf",x+i,y+i);
        for(int i=1;i<=n;i++)
            for(int j=1;j<=n;j++){  
                if(fabs(x[i]-x[j])<eps) continue;   
                double a,b;
                equation(a,b,x[i]*x[i],x[i],y[i],x[j]*x[j],x[j],y[j]);
                if(a>-eps) continue;    
                for(int k=1;k<=n;k++)
                    if(fabs(a*x[k]*x[k]+b*x[k]-y[k])<eps) lines[i][j]|=(1<<(k-1));
            }
        for(int i=0;i<(1<<n);i++){
            int j=lowunbit[i];  
            dp[i|(1<<(j-1))]=min(dp[i|(1<<(j-1))],dp[i]+1); 
            for(int k=1;k<=n;k++) dp[i|lines[j][k]]=min(dp[i|lines[j][k]],dp[i]+1); 
        }
        printf("%d\n",dp[(1<<n)-1]);    
    }
}