Submission #306012

#	Time	Username	Problem	Language	Result	Execution time	Memory
306012		llaki	Stations (IOI20_stations)	Java	8 / 100	1720 ms	38956 KiB

stations

import java.util.ArrayList;

public class stations {

    int[] label(int n, int k, int[] u, int[] v) {
        ArrayList<Integer>[] G = new ArrayList[n];
        for (int i = 0; i < G.length; i++) {
            G[i] = new ArrayList<>();
        }
        for (int i = 0; i < u.length; i++) {
            G[u[i]].add(v[i]);
            G[v[i]].add(u[i]);
        }
        int maxSize = 0;
        for (int i = 0; i < n; i++) {
            maxSize = Math.max(maxSize, G[i].size());
        }
        int[] labels = new int[n];
        if (maxSize > 0) {
            for (int i = 0; i < n; i++) {
                labels[i] = i;
            }
            return labels;
        }
        int leaf = -1;
        for (int i = 0; i < n; i++) {
            if (G[i].size() == 1) {
                leaf = i;
                break;
            }
        }
        int cur = 0;
        int node = leaf;
        int prev = -1;
        while (true) {
            labels[node] = cur;
            cur++;
            boolean found = false;
            for (int to : G[node]) {
                if (to == prev) continue;
                prev = node;
                node = to;
                found = true;
                break;
            }
            if (!found) break;
        }
        return labels;
    }

    boolean isAncestor(int a, int b) {
        if (a == b) return true;
        while (a > 0) {
            a = (a - 1) / 2;
            if (a == b) return true;
        }
        return false;
    }

    int find_next_station(int s, int t, int[] c) {
        if (!isAncestor(t, s)) {
            return (s - 1) / 2;
        }
        for (int nd : c) {
            if (nd < s) continue;
            if (isAncestor(t, nd)) {
                return nd;
            }
        }
//        for (int nd : c) {
//            if (s <= nd && nd <= t) return nd;
//            if (s >= nd && nd >= t) return nd;
//        }
        return -1;
    }
}

Compilation message (stderr)

Note: stations.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.

• Subtask 1: 0 / 5
• Subtask 2: 8 / 8
• Subtask 3: 0 / 16
• Subtask 4: 0 / 10
• Subtask 5: 0 / 61