Submission #416357

#	Time	Username	Problem	Language	Result	Execution time	Memory
416357		model_code	Diamond Hands (innopolis2021_final_B)	Java	100 / 100	879 ms	32704 KiB

Main

import java.io.*;
import java.util.*;

/**
 * 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;
        FastScanner in = new FastScanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Polyline solver = new Polyline();
        solver.solve(1, in, out);
        out.close();
    }

    static class Polyline {
        public void solve(int testNumber, FastScanner in, PrintWriter out) {
            int n = in.nextInt() + 1;
            int[] x = new int[n];
            int[] y = new int[n];
            for (int i = 1; i < n; i++) {
                x[i] = in.nextInt();
                y[i] = in.nextInt();
            }
            for (int i = 1; i < n; i++) {
                if ((x[i] + y[i] + x[0] + y[0]) % 2 != 0) {
                    out.println(-1);
                    return;
                }
                if (Math.abs(y[i] - y[i - 1]) > x[i] - x[i - 1]) {
                    out.println(-1);
                    return;
                }
            }

            int INF = Integer.MAX_VALUE / 2;
            int[][] dp = new int[2][n];
            int[][] pr = new int[2][n];
            Arrays.fill(dp[0], INF);
            Arrays.fill(dp[1], INF);
            dp[0][0] = 1;
            dp[1][0] = 1;
            // d = 0 -> dy/dx = -1
            // d = 1 -> dy/dx = 1
            for (int i = 0; i < n - 1; i++) {
                for (int d = 0; d < 2; d++) {
                    int dpVal = dp[d][i];
                    if (y[i + 1] - y[i] == (x[i + 1] - x[i]) * (2 * d - 1) && dp[d][i + 1] > dpVal) {
                        dp[d][i + 1] = dpVal;
                        pr[d][i + 1] = d;
                    }
                    if (Math.abs(y[i + 1] - y[i]) < (x[i + 1] - x[i]) && dp[d][i + 1] > dpVal + 2) {
                        dp[d][i + 1] = dpVal + 2;
                        pr[d][i + 1] = d;
                    }
                    if (dp[d ^ 1][i + 1] > dpVal + 1) {
                        dp[d ^ 1][i + 1] = dpVal + 1;
                        pr[d ^ 1][i + 1] = d;
                    }
                }
            }
            List<Integer> ansX = new ArrayList<>(), ansY = new ArrayList<>();
            ansX.add(x[n - 1]);
            ansY.add(y[n - 1]);

            int d = dp[0][n - 1] < dp[1][n - 1] ? 0 : 1;
            for (int i = n - 1; i > 0; i--) {
                int prevD = pr[d][i];
                if (d == prevD) {
                    if (y[i] - y[i - 1] == (x[i] - x[i - 1]) * (2 * d - 1)) {
                        // skip point
                    } else {
                        // two intermediate points
                        int delta = (y[i] - (y[i - 1] + (2 * prevD - 1) * (x[i] - x[i - 1]))) / -(2 * prevD - 1);
                        if (delta % 2 != 0 || delta < 0) {
                            throw new AssertionError();
                        }
                        ansX.add(x[i - 1] + delta / 2);
                        ansY.add(y[i - 1] - delta / 2 * (2 * d - 1));
                        ansX.add(x[i - 1]);
                        ansY.add(y[i - 1]);
                    }
                } else {
                    int delta = (y[i] - (y[i - 1] + (2 * prevD - 1) * (x[i] - x[i - 1]))) / -(2 * prevD - 1);
                    if (delta % 2 != 0 || delta < 0) {
                        throw new AssertionError();
                    }
                    ansX.add(x[i] - delta / 2);
                    ansY.add(y[i] - delta / 2 * (2 * d - 1));
                }
                d = prevD;
            }
            ansX.add(x[0]);
            ansY.add(y[0]);
            Collections.reverse(ansX);
            Collections.reverse(ansY);
            out.println(ansX.size() - 1);
            for (int i = 0; i + 1 < ansX.size(); i++) {
                int l = ansX.get(i + 1) - ansX.get(i);
                char c = ansY.get(i + 1) > ansY.get(i) ? '+' : '-';
                out.println(l + " " + c);
            }
        }

    }

    static class FastScanner {
        public BufferedReader br;
        public StringTokenizer st;

        public FastScanner(InputStream in) {
            br = new BufferedReader(new InputStreamReader(in));
        }

        public FastScanner(String fileName) {
            try {
                br = new BufferedReader(new FileReader(fileName));
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public String next() {
            while (st == null || !st.hasMoreElements()) {
                String line = null;
                try {
                    line = br.readLine();
                } catch (IOException e) {
                    throw new UnknownError();
                }
                if (line == null) {
                    throw new UnknownError();
                }
                st = new StringTokenizer(line);
            }
            return st.nextToken();
        }

    }
}

• Subtask 1: 6 / 6
• Subtask 2: 8 / 8
• Subtask 3: 10 / 10
• Subtask 4: 28 / 28
• Subtask 5: 17 / 17
• Subtask 6: 31 / 31