[PAT] 1148 Werewolf

Werewolf（狼人杀） is a game in which the players are partitioned into two parties: the werewolves and the human beings. Suppose that in a game,

• player #1 said: "Player #2 is a werewolf.";
• player #2 said: "Player #3 is a human.";
• player #3 said: "Player #4 is a werewolf.";
• player #4 said: "Player #5 is a human."; and
• player #5 said: "Player #4 is a human.".

Given that there were 2 werewolves among them, at least one but not all the werewolves were lying, and there were exactly 2 liars. Can you point out the werewolves?

Now you are asked to solve a harder version of this problem: given that there were NNN players, with 2 werewolves among them, at least one but not all the werewolves were lying, and there were exactly 2 liars. You are supposed to point out the werewolves.

Input Specification:

Each input file contains one test case. For each case, the first line gives a positive integer NNN (5≤N≤1005 le N le 1005≤N≤100). Then NNN lines follow and the iii-th line gives the statement of the iii-th player (1≤i≤N1 le i le N1≤i≤N), which is represented by the index of the player with a positive sign for a human and a negative sign for a werewolf.

Output Specification:

If a solution exists, print in a line in ascending order the indices of the two werewolves. The numbers must be separated by exactly one space with no extra spaces at the beginning or the end of the line. If there are more than one solution, you must output the smallest solution sequence -- that is, for two sequences A=a[1],...,a[M]A = { a[1], ..., a[M] }A=a[1],...,a[M] and B=b[1],...,b[M]B = { b[1], ..., b[M] }B=b[1],...,b[M], if there exists 0≤k<M0 le k < M0≤k<M such that a[i]=b[i]a[i]=b[i]a[i]=b[i] (i≤ki le ki≤k) and a[k+1]<b[k+1]a[k+1]<b[k+1]a[k+1]<b[k+1], then AAA is said to be smaller than BBB. In case there is no solution, simply print No Solution.

Sample Input 1:

5
-2
+3
-4
+5
+4

Sample Output 1:

1 4

Sample Input 2:

6
+6
+3
+1
-5
-2
+4

Sample Output 2 (the solution is not unique):

1 5

Sample Input 3:

5
-2
-3
-4
-5
-1

Sample Output 3:

No Solution

package pattest;

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

/**
 * @Auther: Xingzheng Wang
 * @Date: 2019/2/27 21:34
 * @Description: pattest
 * @Version: 1.0
 */
public class PAT1148 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] v = new int[n + 1];
        for (int i = 1; i <= n; i++)v[i] = sc.nextInt();
        for (int i = 1; i <= n; i++) {
            for (int j = i + 1; j <= n; j++) {
                List<Integer> lie = new ArrayList<>();
                int[] a = new int[n + 1];
                for (int k = 0; k <= n ; k++) {
                    a[k] = 1;
                }
                a[i] = a[j] = -1;
                for (int k = 1; k <= n; k++) {
                    if (v[k] * a[Math.abs(v[k])] < 0) lie.add(k);
                }
                if (lie.size() == 2 && a[lie.get(0)] + a[lie.get(1)] == 0) {
                    System.out.print(i + " " + j);
                    return;
                }
            }
        }
        System.out.print("No Solution");
    }
}