前端工程師-2020版

download:前端工程師-2020版

前端開發相比其餘IT開發崗位，門檻更低，更易上手，更適合初學者學習
近幾年的前端職業趨勢逐漸走高。薪資可觀，前景看好，如今入行剛恰好！

import java.io.OutputStream; import java.io.IOException; import java.io.InputStream; import java.io.PrintWriter; import java.util.SortedSet; import java.util.Set; import java.util.NavigableSet; import java.io.IOException; import java.io.InputStreamReader; import java.util.TreeSet; import java.util.ArrayList; import java.util.List; import java.util.StringTokenizer; import java.io.BufferedReader; import java.util.Comparator; import java.util.Collections; import java.io.InputStream; /* Built using CHelper plug-in Actual solution is at the top / public class Main { public static void main(String[] args) { InputStream inputStream = System.in; OutputStream outputStream = System.out; InputReader in = new InputReader(inputStream); PrintWriter out = new PrintWriter(outputStream); TaskH solver = new TaskH(); solver.solve(1, in, out); out.close(); } static class TaskH { public void solve(int testNumber, InputReader in, PrintWriter out) { int n = in.nextInt(); int len = in.nextInt(); int[] x = new int[n]; int[] y = new int[n]; double[] s = new double[n]; for (int i = 0; i < n; ++i) { x[i] = in.nextInt(); y[i] = in.nextInt(); s[i] = in.nextDouble(); } List<TaskH.Segment> segments = new ArrayList<>(); int pos = 0; for (int i = 0; i < n; ++i) { if (x[i] > pos) { segments.add(new TaskH.Segment(pos, x[i], 0.0)); } segments.add(new TaskH.Segment(x[i], y[i], s[i])); pos = y[i]; } if (pos < len) { segments.add(new TaskH.Segment(pos, len, 0.0)); } out.println(solveOne(segments)); } private double solveOne(List<TaskH.Segment> segments) { int n = segments.size(); for (int i = 0; i < n; ++i) { TaskH.Segment s = segments.get(i); s.ptr = i; s.curEnergy = 0.0; s.maxEnergy = (s.right - s.left) / s.s; s.minEnergy = -(s.right - s.left) / (s.s + 2); } List<TaskH.Segment> segmentsByS = new ArrayList<>(segments); Collections.sort(segmentsByS, new Comparator<TaskH.Segment>() { public int compare(TaskH.Segment o1, TaskH.Segment o2) { int z = Double.compare(o2.s, o1.s); if (z == 0) { z = Integer.compare(o2.left, o1.left); } return z; } }); TreeSet<TaskH.Segment> available = new TreeSet<>(new Comparator<TaskH.Segment>() { public int compare(TaskH.Segment o1, TaskH.Segment o2) { return o1.ptr - o2.ptr; } }); available.addAll(segments); for (TaskH.Segment s : segmentsByS) { if (s.s == 0.0) break; s.alive = false; available.remove(s); NavigableSet<TaskH.Segment> after = available.tailSet(s, false); double capacity = s.maxEnergy - s.curEnergy; double spent = 0.0; while (!after.isEmpty()) { TaskH.Segment t = after.first(); if (t.alive) { double t1 = t.curEnergy - t.minEnergy; double t2 = capacity - spent; double transfer = Math.min(t1, t2); spent += transfer; t.curEnergy -= transfer; if (t1 <= t2) { available.remove(t); } else { break; } } } s.curEnergy += spent; } double res = 0.0; for (TaskH.Segment s : segments) { double v = (s.right - s.left - s.curEnergy * s.s) / (s.right - s.left + s.curEnergy); res += (s.right - s.left) / (s.s + v); } return res; } static class Segment { int left; int right; int ptr; double s; boolean alive = true; double minEnergy; double curEnergy; double maxEnergy; public Segment(int left, int right, double s) { this.left = left; this.right = right; this.s = s; } } } static class InputReader { public BufferedReader reader; public StringTokenizer tokenizer; public InputReader(InputStream stream) { reader = new BufferedReader(new InputStreamReader(stream), 32768); tokenizer = null; } public String next() { while (tokenizer == null || !tokenizer.hasMoreTokens()) { try { tokenizer = new StringTokenizer(reader.readLine()); } catch (IOException e) { throw new RuntimeException(e); } } return tokenizer.nextToken(); } public int nextInt() { return Integer.parseInt(next()); } public double nextDouble() { return Double.parseDouble(next()); } }