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https://git.sb/baoshuo/OI-codes.git
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83 lines
1.9 KiB
C++
83 lines
1.9 KiB
C++
#include <iostream>
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#include <chrono>
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#include <cmath>
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#include <iomanip>
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#include <random>
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#include <tuple>
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#include <utility>
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#include <vector>
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using std::cin;
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using std::cout;
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const char endl = '\n';
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int main() {
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std::ios::sync_with_stdio(false);
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cin.tie(nullptr);
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int n;
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cin >> n;
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std::vector<std::tuple<int, int, int>> a(n);
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for (auto &o : a) {
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cin >> std::get<0>(o) >> std::get<1>(o) >> std::get<2>(o);
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}
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std::mt19937 gen(std::chrono::system_clock::now().time_since_epoch().count());
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auto random = [&](int low, int high) -> int {
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std::uniform_int_distribution<> dist(low, high);
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return dist(gen);
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};
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auto potential_energy = [&](double x, double y) -> double {
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double res = 0;
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for (auto &o : a) {
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double xx = x - std::get<0>(o),
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yy = y - std::get<1>(o);
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res += std::sqrt(std::pow(xx, 2) + std::pow(yy, 2)) * std::get<2>(o);
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}
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return res;
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};
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double ans_x = 0,
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ans_y = 0,
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ans = 1e18;
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for (int i = 1; i <= 10; i++) {
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double xx = ans_x,
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yy = ans_y;
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double t = 21000;
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while (t > 1e-15) {
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double tmp_x = ans_x + random(-100000, 100000) * t,
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tmp_y = ans_y + random(-100000, 100000) * t;
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double tmp_ans = potential_energy(tmp_x, tmp_y);
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double delta = tmp_ans - ans;
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if (delta < 0) {
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ans_x = xx = tmp_x;
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ans_y = yy = tmp_y;
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ans = tmp_ans;
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} else if (std::exp(-delta / t) * 10000 > random(0, 10000)) {
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xx = tmp_x;
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yy = tmp_y;
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}
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t *= 0.998;
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}
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}
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cout << std::fixed << std::setprecision(3) << ans_x << ' '
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<< std::fixed << std::setprecision(3) << ans_y << endl;
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return 0;
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}
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