岗位是安卓开发。由于不太会图相关的算法,所以都是用BFS解决的,运气好都A了。
第一题,修桥。
import java.util.*; public class Q1_20200913 { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int times = sc.nextInt(); for (int o = 0; o < times; o++) { int n = sc.nextInt(); int m = sc.nextInt(); int limit = sc.nextInt(); List<Integer>[] bridges = new List[n + 1]; for (int i = 0; i < n + 1; i++) { bridges[i] = new LinkedList<>(); } for (int i = 0; i < m; i++) { int l = sc.nextInt(); int r = sc.nextInt(); int cost = sc.nextInt(); if (cost <= limit) { bridges[l].add(r); bridges[r].add(l); } } HashSet<Integer> arrived = new HashSet<>(); Deque<Integer> list = new LinkedList<>(bridges[1]); while (!list.isEmpty()) { int cur = list.poll(); arrived.add(cur); for (Integer i : bridges[cur]) { if (!arrived.contains(i)) { arrived.add(i); list.add(i); } } } if (arrived.size() == n) { System.out.println("Yes"); } else { System.out.println("No"); } } } }
import java.util.*; public class Q2_20200913 { public static void main(String[] args) { Scanner sc = new Scanner(System.in); while (sc.hasNext()) { int n = sc.nextInt(); int m = sc.nextInt(); List<int[]>[] ways = new List[n + 1]; for (int i = 0; i < n + 1; i++) { ways[i] = new ArrayList<>(); } for (int i = 0; i < m; i++) { int l = sc.nextInt(); int r = sc.nextInt(); int cost = sc.nextInt(); int[] lr = {r, cost}; ways[l].add(lr); int[] rl = {l, cost}; ways[r].add(rl); } int start = sc.nextInt(); int tar = sc.nextInt(); String time = sc.next(); int[] arrived = new int[n + 1]; Arrays.fill(arrived, Integer.MAX_VALUE); Deque<int[]> list = new LinkedList<>(); list.add(new int[]{start, 0}); while (!list.isEmpty()) { int[] cur = list.poll(); int pos = cur[0]; int cost = cur[1]; if (cost < arrived[pos]) { arrived[pos] = cost; for (int[] arr : ways[pos]) { if (arr[1] + cost < arrived[arr[0]]) { list.add(new int[]{arr[0], arr[1] + cost}); } } } } int res = arrived[tar]; String out = help(res, time); System.out.println(out); } } static int[] months = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; public static String help(int res, String time) { String[] temp = time.split("\\."); int month = Integer.parseInt(temp[0]); temp = temp[1].split("/"); int day = Integer.parseInt(temp[0]); int hour = Integer.parseInt(temp[1]); hour += res; if (hour >= 24) { day += hour / 24; hour = hour % 24; } while (day > months[month]) { day -= months[month]; month++; } StringBuilder arrive = new StringBuilder(); arrive.append(month).append(".") .append(day).append("/").append(hour); return arrive.toString(); } }
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