delete pics to save space

1.1337.cpp

@@ -0,0 +1,46 @@
+#include<cstdio>
+#include<cmath>
+#include<algorithm>
+using namespace std;
+const int maxn=1005;
+const double eps=1e-5;
+struct OBJ { int x,y,w; };
+int n,dx,dy; OBJ a[maxn];
+double x,y,step=20000,tx,ty;
+void move()
+{
+	double mx=0,my=0,len;
+	for(int i=1;i<=n;i++)
+	{
+		len=sqrt((x-a[i].x)*(x-a[i].x)+(y-a[i].y)*(y-a[i].y));
+		if(fabs(len)<eps) continue;
+		mx+=a[i].w*(a[i].x-x)/len;
+		my+=a[i].w*(a[i].y-y)/len;
+	}
+	len=sqrt(mx*mx+my*my);
+	x+=step*mx/len;
+	y+=step*my/len;
+}
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	scanf("%d",&n);
+	for(int i=1;i<=n;i++) scanf("%d%d%d",&a[i].x,&a[i].y,&a[i].w);
+	while(step>=eps)
+	{
+		tx=x,ty=y;
+		move();
+		if(fabs(tx-x)<eps&&fabs(ty-y)<eps) break;
+		if(dx!=(x>tx)||dy!=(y>ty))
+		{
+			dx=x>tx;
+			dy=y>ty;
+			step=step*0.5;
+		}
+//		printf(">>> %.3lf %.3lf\n",x,y);
+	}
+	printf("%.3lf %.3lf\n",x,y);
+	return 0;
+}