Submission #746185

# Submission time Handle Problem Language Result Execution time Memory
746185 2023-05-21T18:10:12 Z rahulverma Network (BOI15_net) Java 11
100 / 100
1814 ms 158776 KB
import java.io.*;
import java.util.*;

public class net {

	public static void main(String[] args) throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int n = Integer.parseInt(br.readLine());
		ArrayList<ArrayList<Integer>> graph = new ArrayList<>();
		for(int i = 0; i < n; i++) graph.add(new ArrayList<Integer>());
		for(int i = 1; i < n; i++) {
			StringTokenizer st = new StringTokenizer(br.readLine());
			int v1 = Integer.parseInt(st.nextToken()) - 1;
			int v2 =Integer.parseInt(st.nextToken()) - 1;
			graph.get(v1).add(v2);
			graph.get(v2).add(v1);
		}
		int root = 0;
		for(int i = 0; i < n; i++) {
			if(graph.get(i).size() != 1) {
				root = i;
			}
		}
		int[] dist = new int[n];
		Queue<Integer> q = new LinkedList<Integer>();
		Arrays.fill(dist, -1);
		q.add(root);
		dist[root] = 0;
		ArrayList<Integer> ans = new ArrayList<Integer>();
		while(!q.isEmpty()) {
			int node = q.poll();
			for(int node2: graph.get(node)) {
				if(dist[node2] == -1) {
					dist[node2] = dist[node] + 1;
					q.add(node2);
					if(graph.get(node2).size() == 1) {
						ans.add(node2 + 1);
					}
				}
			}
		}

		PrintWriter pw = new PrintWriter(System.out);
		pw.println((ans.size() + 1) / 2);
		for(int i = 0; i < ans.size() / 2; i++) {
			pw.println(ans.get(i) + " " + ans.get(i + ans.size() / 2));
		}
		if(ans.size() % 2 == 1) {
			pw.println(ans.get(ans.size() - 1) + " " + ans.get(0));
		}
		pw.close();
	}

}
# Verdict Execution time Memory Grader output
1 Correct 108 ms 10376 KB Output is correct
2 Correct 110 ms 10428 KB Output is correct
3 Correct 118 ms 10204 KB Output is correct
4 Correct 110 ms 10308 KB Output is correct
5 Correct 113 ms 10472 KB Output is correct
6 Correct 118 ms 10236 KB Output is correct
7 Correct 112 ms 10364 KB Output is correct
8 Correct 110 ms 10336 KB Output is correct
9 Correct 113 ms 10396 KB Output is correct
10 Correct 121 ms 10484 KB Output is correct
11 Correct 122 ms 10532 KB Output is correct
12 Correct 114 ms 10352 KB Output is correct
13 Correct 126 ms 10276 KB Output is correct
14 Correct 116 ms 10416 KB Output is correct
15 Correct 116 ms 10348 KB Output is correct
16 Correct 115 ms 10352 KB Output is correct
17 Correct 117 ms 10228 KB Output is correct
18 Correct 110 ms 10472 KB Output is correct
19 Correct 108 ms 10428 KB Output is correct
20 Correct 106 ms 10472 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 108 ms 10376 KB Output is correct
2 Correct 110 ms 10428 KB Output is correct
3 Correct 118 ms 10204 KB Output is correct
4 Correct 110 ms 10308 KB Output is correct
5 Correct 113 ms 10472 KB Output is correct
6 Correct 118 ms 10236 KB Output is correct
7 Correct 112 ms 10364 KB Output is correct
8 Correct 110 ms 10336 KB Output is correct
9 Correct 113 ms 10396 KB Output is correct
10 Correct 121 ms 10484 KB Output is correct
11 Correct 122 ms 10532 KB Output is correct
12 Correct 114 ms 10352 KB Output is correct
13 Correct 126 ms 10276 KB Output is correct
14 Correct 116 ms 10416 KB Output is correct
15 Correct 116 ms 10348 KB Output is correct
16 Correct 115 ms 10352 KB Output is correct
17 Correct 117 ms 10228 KB Output is correct
18 Correct 110 ms 10472 KB Output is correct
19 Correct 108 ms 10428 KB Output is correct
20 Correct 106 ms 10472 KB Output is correct
21 Correct 115 ms 10248 KB Output is correct
22 Correct 270 ms 14620 KB Output is correct
23 Correct 260 ms 14592 KB Output is correct
24 Correct 246 ms 14752 KB Output is correct
25 Correct 221 ms 14092 KB Output is correct
26 Correct 215 ms 11976 KB Output is correct
27 Correct 258 ms 14672 KB Output is correct
28 Correct 254 ms 14812 KB Output is correct
29 Correct 200 ms 11900 KB Output is correct
30 Correct 127 ms 10492 KB Output is correct
31 Correct 269 ms 14752 KB Output is correct
32 Correct 116 ms 10372 KB Output is correct
33 Correct 120 ms 10224 KB Output is correct
34 Correct 132 ms 10196 KB Output is correct
35 Correct 117 ms 10444 KB Output is correct
36 Correct 125 ms 10652 KB Output is correct
37 Correct 149 ms 10648 KB Output is correct
38 Correct 161 ms 10836 KB Output is correct
39 Correct 116 ms 10228 KB Output is correct
40 Correct 118 ms 10372 KB Output is correct
41 Correct 143 ms 10268 KB Output is correct
42 Correct 131 ms 10572 KB Output is correct
43 Correct 155 ms 10792 KB Output is correct
44 Correct 116 ms 10508 KB Output is correct
45 Correct 128 ms 10480 KB Output is correct
46 Correct 155 ms 10636 KB Output is correct
47 Correct 128 ms 10548 KB Output is correct
48 Correct 127 ms 10352 KB Output is correct
49 Correct 148 ms 11168 KB Output is correct
50 Correct 130 ms 10372 KB Output is correct
51 Correct 123 ms 10300 KB Output is correct
52 Correct 127 ms 10544 KB Output is correct
53 Correct 140 ms 10776 KB Output is correct
54 Correct 123 ms 10292 KB Output is correct
55 Correct 144 ms 10504 KB Output is correct
56 Correct 115 ms 10436 KB Output is correct
57 Correct 133 ms 10704 KB Output is correct
58 Correct 234 ms 14404 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 108 ms 10376 KB Output is correct
2 Correct 110 ms 10428 KB Output is correct
3 Correct 118 ms 10204 KB Output is correct
4 Correct 110 ms 10308 KB Output is correct
5 Correct 113 ms 10472 KB Output is correct
6 Correct 118 ms 10236 KB Output is correct
7 Correct 112 ms 10364 KB Output is correct
8 Correct 110 ms 10336 KB Output is correct
9 Correct 113 ms 10396 KB Output is correct
10 Correct 121 ms 10484 KB Output is correct
11 Correct 122 ms 10532 KB Output is correct
12 Correct 114 ms 10352 KB Output is correct
13 Correct 126 ms 10276 KB Output is correct
14 Correct 116 ms 10416 KB Output is correct
15 Correct 116 ms 10348 KB Output is correct
16 Correct 115 ms 10352 KB Output is correct
17 Correct 117 ms 10228 KB Output is correct
18 Correct 110 ms 10472 KB Output is correct
19 Correct 108 ms 10428 KB Output is correct
20 Correct 106 ms 10472 KB Output is correct
21 Correct 115 ms 10248 KB Output is correct
22 Correct 270 ms 14620 KB Output is correct
23 Correct 260 ms 14592 KB Output is correct
24 Correct 246 ms 14752 KB Output is correct
25 Correct 221 ms 14092 KB Output is correct
26 Correct 215 ms 11976 KB Output is correct
27 Correct 258 ms 14672 KB Output is correct
28 Correct 254 ms 14812 KB Output is correct
29 Correct 200 ms 11900 KB Output is correct
30 Correct 127 ms 10492 KB Output is correct
31 Correct 269 ms 14752 KB Output is correct
32 Correct 116 ms 10372 KB Output is correct
33 Correct 120 ms 10224 KB Output is correct
34 Correct 132 ms 10196 KB Output is correct
35 Correct 117 ms 10444 KB Output is correct
36 Correct 125 ms 10652 KB Output is correct
37 Correct 149 ms 10648 KB Output is correct
38 Correct 161 ms 10836 KB Output is correct
39 Correct 116 ms 10228 KB Output is correct
40 Correct 118 ms 10372 KB Output is correct
41 Correct 143 ms 10268 KB Output is correct
42 Correct 131 ms 10572 KB Output is correct
43 Correct 155 ms 10792 KB Output is correct
44 Correct 116 ms 10508 KB Output is correct
45 Correct 128 ms 10480 KB Output is correct
46 Correct 155 ms 10636 KB Output is correct
47 Correct 128 ms 10548 KB Output is correct
48 Correct 127 ms 10352 KB Output is correct
49 Correct 148 ms 11168 KB Output is correct
50 Correct 130 ms 10372 KB Output is correct
51 Correct 123 ms 10300 KB Output is correct
52 Correct 127 ms 10544 KB Output is correct
53 Correct 140 ms 10776 KB Output is correct
54 Correct 123 ms 10292 KB Output is correct
55 Correct 144 ms 10504 KB Output is correct
56 Correct 115 ms 10436 KB Output is correct
57 Correct 133 ms 10704 KB Output is correct
58 Correct 234 ms 14404 KB Output is correct
59 Correct 1736 ms 118804 KB Output is correct
60 Correct 1783 ms 119776 KB Output is correct
61 Correct 111 ms 10416 KB Output is correct
62 Correct 117 ms 10288 KB Output is correct
63 Correct 1474 ms 112388 KB Output is correct
64 Correct 304 ms 14872 KB Output is correct
65 Correct 447 ms 18852 KB Output is correct
66 Correct 737 ms 49376 KB Output is correct
67 Correct 1513 ms 115816 KB Output is correct
68 Correct 1644 ms 116132 KB Output is correct
69 Correct 543 ms 18544 KB Output is correct
70 Correct 902 ms 57584 KB Output is correct
71 Correct 1748 ms 156944 KB Output is correct
72 Correct 1814 ms 144004 KB Output is correct
73 Correct 827 ms 42040 KB Output is correct
74 Correct 1703 ms 118404 KB Output is correct
75 Correct 636 ms 28328 KB Output is correct
76 Correct 1693 ms 151640 KB Output is correct
77 Correct 1738 ms 158776 KB Output is correct
78 Correct 598 ms 25608 KB Output is correct
79 Correct 1462 ms 115948 KB Output is correct
80 Correct 353 ms 14948 KB Output is correct
81 Correct 896 ms 55616 KB Output is correct
82 Correct 1805 ms 146448 KB Output is correct
83 Correct 1725 ms 118716 KB Output is correct
84 Correct 1678 ms 118320 KB Output is correct
85 Correct 1726 ms 118764 KB Output is correct
86 Correct 1804 ms 119440 KB Output is correct
87 Correct 1789 ms 119460 KB Output is correct