高斯小圆。
#include<cstdio>#include<iostream>#include<cmath>#include<cstring>#include<algorithm>#include<set>#include<map>using namespace std;#define rep(i,l,r) for(register int i=(l);i<=(r);++i)#define repdo(i,l,r) for(register int i=(l);i>=(r);--i)#define il inlinetypedef double db;typedef long long ll;//---------------------------------------const int nsz=25;const db eps=1e-8;int n;db line[nsz][nsz],a[nsz][nsz],ans[nsz];int gauss(){ ???int p0; ???db tmp; ???rep(i,1,n){ ???????p0=i; ???????rep(j,i+1,n)if(fabs(a[p0][i])<fabs(a[j][i]))p0=j; ???????if(p0!=i)rep(j,1,n+1)swap(a[i][j],a[p0][j]); ???????if(fabs(a[i][i])<eps)return 0; ???????rep(j,1,n){ ???????????if(j==i)continue; ???????????tmp=a[j][i]/a[i][i]; ???????????rep(k,i+1,n+1)a[j][k]-=a[i][k]*tmp; ???????} ???} ???rep(i,1,n)a[i][n+1]/=a[i][i],ans[i]=a[i][n+1]; ???return 1;}il db p2(db v){return v*v;}void sol(){ ???rep(i,2,n+1){ ???????rep(j,1,n){ ???????????a[i-1][j]+=2*(line[i][j]-line[1][j]); ???????????a[i-1][n+1]+=p2(line[i][j])-p2(line[1][j]); ???????} ???} ???gauss();}int main(){ ???ios::sync_with_stdio(0),cin.tie(0); ???cin>>n; ???rep(i,1,n+1)rep(j,1,n)cin>>line[i][j]; ???sol(); ???rep(i,1,n)printf("%.3lf ",ans[i]); ???return 0;}bzoj1013-[JSOI2008]球形空间产生器
原文地址：https://www.cnblogs.com/ubospica/p/9829508.html