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\documentclass{ctexart}
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\usepackage{graphicx}
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\usepackage{amsmath}
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\usepackage{geometry}
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\usepackage{lmodern}
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\usepackage{fontspec}
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\usepackage{pdfpages}
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\usepackage{listings}
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\geometry{a4paper,scale=0.75}
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\pagestyle{empty}
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\begin{document}
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\includepdf[pages=-]{4.pdf}
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\includepdf[pages=-]{省选基础算法.pdf}
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\includepdf[pages=-]{1.pdf}
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\includepdf[pages=-]{2.pdf}
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\includepdf[pages=-]{3.pdf}
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\section*{hxd's debug list}
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\begin{quotation}
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ACM本就逆风而行，在去机房的路上被风吹翻很正常。
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\end{quotation}
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\begin{itemize}
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\item
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线段树要开4倍内存
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\item
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cin跑得超级慢
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\item
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memset 比 for循环快得多
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\begin{itemize}
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\item
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memset总是清空整个数组，有时候只清理要用到的部分用for也许更好。
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\end{itemize}
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\item
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有多组数据时要清空全局变量（以及各种队列）
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\item
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\texttt{std::accumulate} 的返回类型由第三个参数（初始值）决定。
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\item
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进bfs的时候要记得push初始状态。 / front后记得pop。
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\item
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检查输出编号是否在范围内(0)。
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\item
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检查不存在可行解时的输出(-1)。
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\item
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cin不仅跑得慢，而且跑得超级无敌螺旋飞天香蕉船慢。
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\item
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当你怎么样都过不了的时候（显然不会TLE的东西TLE了或者RE），试试把数组开大十倍，有可能是题面打错了。
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\item
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explicit specialization of 'template<class \_Tp> struct std::hash' outside its namespace must use a nested-name-specifier [-fpermissive].
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for example: struct std::hash<pair<int, int> > but not struct hash<pair<int, int> >
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\item
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看题目数据范围，或许会出现$r-l \leq 2$这样的东西。
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\end{itemize}
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\includepdf[pages=-]{A_brief_introduction_to_pb_ds_for_ICPC.pdf}
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\includepdf[pages=-]{ICPC_Howtos_20190428.pdf}
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\section*{模拟退火}
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\begin{lstlisting}
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#include <cmath>
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#include <cstdio>
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#include <cstdlib>
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#include <ctime>
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#include <iostream>
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using namespace std;
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double y;
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double F(double x) {
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return 6 * pow(x, 7) + 8 * pow(x, 6)
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+ 7 * pow(x, 3) + 5 * pow(x, 2) - y * x;
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}
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double Rand01() { return rand() / (double)RAND_MAX; }
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double Rand(double T) {
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int f = rand() & 1;
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return (f ? -1 : 1) * T * Rand01();
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}
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int main() {
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srand(time(NULL));
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int Case;
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scanf("%d", &Case);
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while (Case--) {
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scanf("%lf", &y);
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double T = 100, T_end = 1e-6, d = 0.85, ans = F(0);
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// T 初始温度，T_end 结束冷却温度，d 降温系数，ans 答案
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double x_now = 0, x_next;
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while (T > T_end) {
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for (int i = 0; i < 2; i++) {
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x_next = x_now + Rand(T);
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//他手写的rand就是【-1,1】随机 取一个然后*t*（1 or -1）
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if (x_next < 0 || x_next > 100)
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continue;
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//不科学就continue
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double f_next = F(x_next), f_now = F(x_now);
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//计算现在与之前的值
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double delta = f_next - f_now; //计算差值
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cout << x_now << x_next << Rand01() << endl;
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if (delta < 0 || Rand01() < exp(-delta / T)) {
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// delta<0表示下一个解比当前解更优哇
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// （函数值更小）或者是概率接受记死exp（-delta/T）
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x_now = x_next; //修改啊哈哈
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ans = min(ans, f_next); //题目要求最小x是ans
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}
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}
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T *= d; //降温啦啦啦
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}
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printf("%.4f\n", ans);
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}
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return 0;
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}
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\end{lstlisting}
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\begin{verbatim}
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#include <bits/stdc++.h>
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using namespace std;
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const int maxn = 1e3 + 5;
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const double inf = 1e80;
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struct xd {
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double a, b, c, d;
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} xx[maxn];
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int n;
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double l;
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struct Point {
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double x, y;
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};
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double dis(Point x, Point y) {
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return sqrt((x.x - y.x) * (x.x - y.x) + (x.y - y.y) * (x.y - y.y));
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}
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double cos(double a, double b, double c) {
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return (b * b + c * c - a * a) / (2 * b * c);
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}
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double dis(Point x, Point a, Point b) {
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double l1 = dis(x, a);
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double l2 = dis(x, b);
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double l3 = dis(a, b);
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if (cos(l1, l2, l3) < 0)
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return l2;
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if (cos(l2, l1, l3) < 0)
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return l1;
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double p = (l1 + l2 + l3) / 2;
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double area = sqrt(p * (p - l1) * (p - l2) * (p - l3));
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return area * 2 / l3;
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}
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double dis(double x, Point a, Point b) { return dis({x, 0}, a, b); }
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double f(double x) {
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double mi = inf;
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for (int i = 1; i <= n; i++) {
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Point aa;
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aa.x = xx[i].a, aa.y = xx[i].b;
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Point bb;
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bb.x = xx[i].c, bb.y = xx[i].d;
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mi = min(mi, dis(x, aa, bb));
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}
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return mi;
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}
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double rand01() { return rand() / (double)RAND_MAX; }
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double randnext(double T) {
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int sgn = rand() & 1;
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double haha = (sgn ? -1 : 1) * T * rand01();
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return haha;
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}
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int p[15];
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int mls = 15;
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int main() {
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int Tt;
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scanf("%d", &Tt);
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while (Tt--) {
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srand(time(NULL));
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scanf("%d%lf", &n, &l);
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for (int i = 1; i <= n; i++) {
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scanf("%lf%lf%lf%lf", &xx[i].a, &xx[i].b, &xx[i].c, &xx[i].d);
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}
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for (int i = 0; i < mls; i++)
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p[i] = rand01() * l;
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double T = l, Tend = 1e-5, d = 0.95, ans = -1e100;
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double id = 0;
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double pos = 0;
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while (T > Tend) {
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for (int i = 0; i < mls; i++) {
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double inmin = -1e100;
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double pmin = p[i];
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for (int i = 0; i < mls; i++) {
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double add = randnext(T);
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if (add + p[i] > l || add + p[i] < 0)
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continue;
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double tp = add + p[i];
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double nexhi = f(tp);
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double delta = inmin - nexhi;
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if (delta < 0) {
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pmin = tp;
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inmin = nexhi;
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}
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}
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p[i] = pmin;
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if (inmin > ans) {
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ans = inmin;
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pos = pmin;
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}
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}
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T *= d;
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}
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cerr << pos << endl;
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printf("%.3lf\n", ans);
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}
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}
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\end{verbatim}
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\end{document} |
