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| #include <bits/stdc++.h>
const int MaxN = 1010;
const double delta = 0.993;
struct node
{
int x, y, w;
};
int n;
node a[MaxN];
double ansx, ansy;
double ans = 1e18, t;
inline int read()
{
bool f = 0;
int x = 0;
char ch = getchar();
while (ch < '0' || ch > '9')
{
if (ch == '-')
f = true;
ch = getchar();
}
while (ch >= '0' && ch <= '9')
x = (x << 1) + (x << 3) + ch - '0', ch = getchar();
return (!f) ? x : -x;
}
double calc(double nx, double ny)
{
double sum = 0;
for (int i = 1; i <= n; i++)
{
double x = nx - a[i].x;
double y = ny - a[i].y;
sum += sqrt(x * x + y * y) * a[i].w;
}
return sum;
}
void sa()
{
double nowx = ansx, nowy = ansy;
t = 1000000;
while (t > 1e-14)
{
double tmpx = ansx + (rand() * 2 - RAND_MAX) * t;
double tmpy = ansy + (rand() * 2 - RAND_MAX) * t;
double tmp = calc(tmpx, tmpy);
if (tmp - ans < 0)
{
nowx = tmpx;
nowy = tmpy;
ansx = tmpx;
ansy = tmpy;
ans = tmp;
}
else if (exp((ans - tmp) / t) * RAND_MAX > rand())
{
nowx = tmpx;
nowy = tmpy;
}
t *= delta;
}
}
int main()
{
n = read();
srand(19260817);
for (int i = 1; i <= n; i++)
a[i].x = read(), a[i].y = read(), a[i].w = read();
sa();
printf("%.3lf %.3lf", ansx, ansy);
return 0;
}
|