ACM学习历程—HDU4717 The Moving Points（模拟退火 || 三分法）

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cstring>
#include <algorithm>
#include <set>
#include <map>
#include <vector>
#include <queue>
#include <string>
#define LL long long
#define eps 1e-5

using namespace std;

typedef pair<double, double> pdd;

int x[305], y[305], vx[305], vy[305], n;
double minT, minDis;

double pow2(double k)
{
    return k*k;
}

double calDis(double t)
{
    double dis2 = 0;
    for (int i = 0; i < n; ++i)
    {
        for (int j = i+1; j < n; ++j)
        {
            if (i == j)
                continue;
            dis2 = max(dis2,
                       pow2(x[i]+vx[i]*t-x[j]-vx[j]*t) + pow2(y[i]+vy[i]*t-y[j]-vy[j]*t));
        }
    }
    return sqrt(dis2);
}

void qt()
{
    double dt = 1e8, t, dis, k = 0.9, v;
    minT = 0;
    minDis = calDis(minT);

    while (dt > eps)
    {
        dis = calDis(minT+dt);
        t = minT + dt;
        if (minT-dt >= 0)
        {
            v = calDis(minT-dt);
            if (v < dis)
            {
                dis = v;
                t = minT - dt;
            }
        }
        if (dis < minDis)
        {
            minDis = dis;
            minT = t;
        }
        dt *= k;
    }
}

void Work()
{
    scanf("%d", &n);
    for (int i = 0; i < n; ++i)
        scanf("%d%d%d%d", &x[i], &y[i], &vx[i], &vy[i]);
    qt();
}

int main()
{
    //freopen("test.in", "r", stdin);
    int T;
    scanf("%d", &T);
    for (int times = 1; times <= T; ++times)
    {
        printf("Case #%d: ", times);
        Work();
        printf("%.2lf %.2lf\n", minT, minDis);
    }
    return 0;
}