【高斯消元】CDOJ1784 曜酱的线性代数课堂（二）

#include<cstdio>
#include<cmath>
#include<algorithm>
#include<cstring>
using namespace std;
const double EPS=0.00000001;
#define N 105
int n,m;
double B

,A

;
int guass_jordan()
{
memcpy(B,A,sizeof(A));
for(int i=1;i<=n;++i)
{
int pivot=i;
for(int j=i+1;j<=n;++j)
if(fabs(B[j][i])>fabs(B[pivot][i]))
pivot=j;
swap(B[i],B[pivot]);
if(fabs(B[i][i])<EPS){
return i-1;
}
for(int j=i+1;j<=m;++j)
B[i][j]/=B[i][i];
for(int j=1;j<=n;++j)
if(i!=j)
for(int k=i+1;k<=m;++k)
B[j][k]-=B[j][i]*B[i][k];
}
return n;
}
int main()
{
while(scanf("%d%d",&n,&m)!=EOF){
memset(A,0,sizeof(A));
for(int i=1;i<=n;++i){
for(int j=1;j<=m;++j){
scanf("%lf",&A[i][j]);
}
}
printf("%d\n",guass_jordan());
}
return 0;
}