give code for this in the format shown in above im...
Tạo vào: 12 tháng 7, 2025
Tạo vào: 12 tháng 7, 2025
The user is asking for Java code to solve a problem. The problem involves maximizing landmarks visited on a bus route, with a budget constraint to be followed.
From the image, the function signature is given as: static void optimalPath(int N, int M, int price, int[] source, int[] dest, int[] weight)
.
I'm going to implement the logic inside this function based on the problem's details, using a way to read input values.
I'll ensure the code fits that required format and effectively addresses the task.
The user is asking for Java code based on a problem described with specific requirements. The task is to print the route taken, where the goal is to visit as many landmarks as possible without exceeding the budget, while considering a return trip.
I will provide a Java code snippet starting with necessary imports, using the format shown in the image. Additionally, I'll replicate the input format and implement a solution involving edge cost and budget management, ensuring the explanation matches the given problem constraints.
optimalPath
I think I need to correctly implement the optimalPath()
function to solve the problem using a depth-first search (DFS) to find the longest path starting from landmark 1. The goal is to maximize the visits to landmarks while ensuring the return journey doesn't exceed the budget. The approach must consider edge weights, visited nodes (to avoid cycles), and the budget constraint (2 * path cost ≤ budget). We’ll output the path including the return route, excluding the last node to avoid repetition.
I’ll also make sure to handle the input format and output using Scanner
and arrays.
javaimport java.io.*; import java.util.*; public class TestClass { /* * N : number of landmarks (numbered 1 … N) * M : number of bus routes * price : total money Julie has * source : array of length M with the start-landmark of each route * dest : array of length M with the end-landmark of each route * weight : array of length M with the ticket price for that route * * The function prints to STDOUT the complete route Julie takes: * the forward journey from landmark 1, followed by the reverse * journey back to landmark 1, every landmark separated by one space. */ static void optimalPath(int N, int M, int price, int[] source, int[] dest, int[] weight) { /* ---------- build an undirected weighted graph ---------- */ List<int[]>[] g = new ArrayList[N + 1]; // g[u] -> {v , w} for (int i = 1; i <= N; i++) g[i] = new ArrayList<>(); for (int i = 0; i < M; i++) { g[source[i]].add(new int[]{dest[i], weight[i]}); g[dest[i]].add(new int[]{source[i], weight[i]}); } /* ---------- DFS to find the longest affordable simple path ---------- */ boolean[] visited = new boolean[N + 1]; List<Integer> current = new ArrayList<>(); List<Integer> best = new ArrayList<>(); dfs(1, 0, price, g, visited, current, best); /* ---------- print the chosen route (go + return) ---------- */ StringBuilder out = new StringBuilder(); for (int v : best) { out.append(v).append(' '); } for (int i = best.size() - 2; i >= 0; i--) { // skip last (already printed) out.append(best.get(i)).append(' '); } // trim trailing space and print System.out.println(out.toString().trim()); } /* helper to explore paths */ private static void dfs(int u, int cost, int budget, List<int[]>[] g, boolean[] visited, List<Integer> cur, List<Integer> best) { visited[u] = true; cur.add(u); /* update best path seen so far */ if (cur.size() > best.size()) { best.clear(); best.addAll(cur); } for (int[] edge : g[u]) { int v = edge[0], w = edge[1]; if (!visited[v] && 2 * (cost + w) <= budget) { // need money to go & return dfs(v, cost + w, budget, g, visited, cur, best); } } /* back-track */ cur.remove(cur.size() - 1); visited[u] = false; } /* ------------------------- driver code ------------------------- */ public static void main(String[] args) throws Exception { Scanner sc = new Scanner(System.in); int N = sc.nextInt(); int M = sc.nextInt(); int price = sc.nextInt(); int[] source = new int[M]; int[] dest = new int[M]; int[] weight = new int[M]; for (int i = 0; i < M; i++) { source[i] = sc.nextInt(); dest[i] = sc.nextInt(); weight[i] = sc.nextInt(); } sc.close(); optimalPath(N, M, price, source, dest, weight); } }