delete pics to save space

8.1013.cpp

@@ -0,0 +1,43 @@
+#include<cstdio>
+using namespace std;
+typedef double LD;
+inline LD abs(const LD &x) { return x<0?-x:x; }
+inline void swap(LD &a,LD &b) { LD t=a; a=b; b=t; }
+int n;
+LD a[15][15],b[15][15];
+void print()
+{
+	for(int i=1;i<=n;i++)
+	{
+		for(int j=0;j<=n;j++) printf("%.3lf ",b[i][j]);
+		puts("");
+	}
+	puts("");
+}
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	scanf("%d",&n);
+	for(int i=1;i<=n+1;i++) for(int j=1;j<=n;j++) scanf("%lf",&a[i][j]);
+	for(int i=1;i<=n;i++)
+		for(int j=1;j<=n;j++)
+		{
+			b[i][j]=2*(a[i][j]-a[i+1][j]);
+			b[i][0]+=a[i][j]*a[i][j]-a[i+1][j]*a[i+1][j];
+		}
+	for(int i=1;i<=n;i++)
+	{
+		int pos=i;
+		for(int j=i+1;j<=n;j++) if(abs(b[j][i])>abs(b[pos][i])) pos=j;
+		for(int j=0;j<=n;j++) swap(b[i][j],b[pos][j]);
+		for(int k=1;k<=n;k++) if(k!=i)
+		{
+			double d=b[k][i]/b[i][i];
+			for(int j=i;j<=n;j++) b[k][j]-=d*b[i][j]; b[k][0]-=d*b[i][0];
+		}
+	}
+	for(int i=1;i<n;i++) printf("%.3lf ",b[i][0]/b[i][i]); printf("%.3lf\n",b[n][0]/b[n][n]);
+	return 0;
+}