\u770b\u5230\\(n<=18\\)\uff0c\u5f88\u5bb9\u6613\u53ef\u4ee5\u60f3\u5230\u72b6\u538b\\(DP\\)\u3002
\n\u6700\u5927\u529b\u7684\u505a\u6cd5\u5c31\u662f\uff0c\u679a\u4e3e\u539f\u96c6\u5408\u548c\u8f6c\u79fb\u7684\u76ee\u7684\u96c6\u5408\uff0c\u7136\u540e\u8003\u8651\u4e00\u6761\u629b\u7269\u7ebf\u80fd\u5426\u7a7f\u8fc7\u5176\u4e2d\u7684\u6240\u6709\u70b9\u3002
\n\u4f46\u662f\u8fd9\u6837\u7684\u590d\u6742\u5ea6\u663e\u7136\u662f\u4e0d\u53ef\u63a5\u53d7\u7684\uff0c\u8003\u8651\u4f18\u5316\u3002
\n\u6613\u77e5\uff0c\u4e09\u70b9\u786e\u5b9a\u4e00\u6761\u629b\u7269\u7ebf\uff0c\u6545\u800c\u5728\u7ed9\u5b9a\\(c=0\\)\u7684\u65f6\u5019\uff0c\u786e\u5b9a\u4e24\u70b9\u5373\u53ef\u786e\u5b9a\u7b2c\u4e09\u70b9\u3002\u5177\u4f53\u7684\u65b9\u7a0b\u7ec4\u662f\uff1a
\n$$a=\\frac{x_{j}*y_{i}-x_{i}*y{j}}{x_{i}*x_{j}*(x_{i}-x_{j})}$$
\n$$b=\\frac{y_{i}}{x_{i}}-a*x_{i}$$
\n\u4ece\u800c\u6211\u4eec\u53ef\u4ee5\u9884\u5904\u7406\u51fa\uff0c\u901a\u8fc7\u67d0\u4e24\u4e2a\u70b9\u7684\u629b\u7269\u7ebf\u901a\u8fc7\u7684\u70b9\u7684\u96c6\u5408\uff0c\u7136\u540e\u5bf9\u4e8e\u6bcf\u4e00\u4e2a\u72b6\u6001\uff0c\u9009\u62e9\u54ea\u4e24\u4e2a\u70b9\u62d3\u5c55\u5373\u53ef\u3002
\n\u4f46\u8fd9\u4e2a\u65f6\u5019\u7684\u65f6\u95f4\u590d\u6742\u5ea6\u662f\\(O(T*n^2*2^n)\\)\uff0c\u5bf9\u4e8e\u8f83\u5927\u7684\u6570\u636e\u8fd8\u662f\u5f88\u96be\u901a\u8fc7\u7684\u3002
\n\u8fd9\u65f6\u5019\u6211\u4eec\u53ef\u4ee5\u53d1\u73b0\uff0c\u7b2c\u4e00\u4e2a\u9009\u62e9\u7684\u70b9\u662f\u53ef\u4ee5\u56fa\u5b9a\u7684\uff0c\u4e5f\u5c31\u662f\u7b2c\u4e00\u4e2a\u53ef\u9009\u62e9\u7684\u70b9\u3002\u56e0\u4e3a\u5982\u679c\u9009\u62e9\u5176\u4ed6\u70b9\u5f00\u59cb\u62d3\u5c55\u7684\u8bdd\uff0c\u5230\u6700\u540e\u4f9d\u7136\u8981\u62d3\u5c55\u90a3\u4e2a\u70b9\u3002
\n\u90a3\u4e48\u5c31\u6210\u529f\u5730\u5c06\u590d\u6742\u5ea6\u538b\u7f29\u5230\u4e86\\(O(T*n*2^n)\\)\uff0c\u8fd9\u65f6\u5019\u5c31\u53ef\u4ee5\u901a\u8fc7\u4e86\u3002
\nPS:\u51e1\u662fDouble\u7684\u9898\u90fd\u5e94\u8be5\u6ce8\u610f\u7cbe\u5ea6\u3002<\/p>\n
#include<iostream>\r\n#include<cstdio>\r\n#include<cstring>\r\nusing namespace std;\r\n#define eps 1E-6\r\nint n,m;\r\nint f[1<<18],A[20][20];\r\ndouble x[20],y[20];\r\ninline int lwbt(const int &_X){\r\n return _X&-_X;\r\n}\r\ninline int Min(const int &_X,const int &_Y){\r\n return _X<_Y?_X:_Y;\r\n}\r\ninline int cnt(int _X){\r\n int rt=0;\r\n while(_X&1){\r\n ++rt;\r\n _X>>=1;\r\n }\r\n return rt;\r\n}\r\nvoid init(){\r\n scanf(\"%d%d\",&n,&m);\r\n for(int i=0;i<n;++i){\r\n scanf(\"%lf%lf\",&x[i],&y[i]);\r\n }\r\n double a,b;\r\n for(int i=0;i<n;++i){\r\n for(int j=i;j<n;++j){\r\n if(x[i]-x[j]<=eps&&x[i]-x[j]>=-eps){\r\n if(!(y[i]-y[j]<=eps&&y[i]-y[j]>=-eps)){\r\n A[i][j]=0;\r\n continue;\r\n }else{\r\n A[i][j]=(1<<i)|(1<<j);\r\n continue;\r\n }\r\n }\r\n a=(x[j]*y[i]-x[i]*y[j])\/(x[i]*x[j]*(x[i]-x[j]));\r\n b=y[i]\/x[i]-a*x[i];\r\n A[i][j]=0;\r\n if(a>=-eps){\r\n continue;\r\n }\r\n for(int k=0;k<n;++k){\r\n if(a*x[k]*x[k]+b*x[k]-y[k]<=eps&&a*x[k]*x[k]+b*x[k]-y[k]>=-eps){\r\n A[i][j]|=(1<<k);\r\n }\r\n }\r\n }\r\n }\r\n \/*\r\n for(int i=0;i<n;++i){\r\n for(int j=0;j<n;++j){\r\n printf(\"%d \",A[i][j]);\r\n }\r\n puts(\"\");\r\n }\r\n *\/\r\n const int MAX=1<<n;\r\n int loc;\r\n memset(f,0x3f,sizeof(f));\r\n f[0]=0;\r\n \r\n for(int i=0;i<MAX;++i){\r\n loc=cnt(i);\r\n for(int j=loc;j<n;++j){\r\n f[i|A[loc][j]]=Min(f[i|A[loc][j]],f[i]+1);\r\n }\r\n }\r\n printf(\"%d\\n\",f[MAX-1]);\r\n}\r\nint main(){\r\n int T;\r\n scanf(\"%d\",&T);\r\n while(T--){\r\n init();\r\n }\r\n return 0;\r\n}<\/code><\/pre>\n <\/p>\n","protected":false},"excerpt":{"rendered":"
\u770b\u5230\\(n<=18\\)\uff0c\u5f88\u5bb9\u6613\u53ef\u4ee5\u60f3\u5230\u72b6\u538b\\(DP\\)\u3002 \u6700\u5927\u529b\u7684\u505a\u6cd5\u5c31\u662f\uff0c\u679a\u4e3e\u539f\u96c6\u5408\u548c\u8f6c\u79fb\u7684\u76ee\u7684\u96c6\u5408\uff0c … <\/p>\n