A、B、C、D、E、F、G、H、I、J 共10名学生有可能参加本次计算机竞赛,也可能不参加。因为某种原因,他们是否参赛受到下列条件的约束:
- 如果A参加,B也参加;
- 如果C不参加,D也不参加;
- A和C中只能有一个人参加;
- B和D中有且仅有一个人参加;
- D、E、F、G、H 中至少有2人参加;
- C和G或者都参加,或者都不参加;
- C、E、G、I中至多只能2人参加
- 如果E参加,那么F和G也都参加。
- 如果F参加,G、H就不能参加
- 如果I、J都不参加,H必须参加
请编程根据这些条件判断这10名同学中参赛者名单。如果有多种可能,则输出所有的可能情况。每种情况占一行。参赛同学按字母升序排列,用空格分隔。
比如:
C D G J
就是一种可能的情况。
多种情况的前后顺序不重要
package com.liu.ex4;
import java.util.ArrayList;
import java.util.Collections;
public class Main {
public static ArrayList<Integer> list = new ArrayList<Integer>();
public boolean judge1() {
boolean judge = true;
if(list.contains(0)) {
if(!list.contains(1))
judge = false;
}
return judge;
}
public boolean judge2() {
boolean judge = true;
if(!list.contains(2)) {
if(list.contains(3))
judge = false;
}
return judge;
}
public boolean judge3() {
boolean judge = true;
if(list.contains(0)) {
if(list.contains(2))
judge = false;
}
return judge;
}
public boolean judge4() {
boolean judge = false;
if(list.contains(1) && !list.contains(3))
judge = true;
else if(!list.contains(1) && list.contains(3))
judge = true;
return judge;
}
public boolean judge5() {
boolean judge = false;
int count = 0;
for(int i = 3;i <= 7;i++) {
if(list.contains(i))
count++;
}
if(count >= 2)
judge = true;
return judge;
}
public boolean judge6() {
boolean judge = false;
if(list.contains(2) && list.contains(6))
judge = true;
else if(!list.contains(2) && !list.contains(6))
judge = true;
return judge;
}
public boolean judge7() {
boolean judge = false;
int count = 0;
if(list.contains(2))
count++;
if(list.contains(4))
count++;
if(list.contains(6))
count++;
if(list.contains(8))
count++;
if(count <= 2)
judge = true;
return judge;
}
public boolean judge8() {
boolean judge = true;
if(list.contains(4)) {
if(list.contains(5) == false || list.contains(6) == false)
judge = false;
}
return judge;
}
public boolean judge9() {
boolean judge = true;
if(list.contains(5)) {
if(list.contains(6) || list.contains(7))
judge = false;
}
return judge;
}
public boolean judge10() {
boolean judge = true;
if(!list.contains(8) && !list.contains(9)) {
if(!list.contains(7))
judge = false;
}
return judge;
}
public boolean check() {
if(judge1() && judge2() && judge3() && judge4() && judge5()) {
if(judge6() && judge7() && judge8() && judge9() && judge10())
return true;
}
return false;
}
public void dfs(int step) {
while(step < 10) {
list.add(step);
if(check()) {
ArrayList<Integer> tempList = new ArrayList<Integer>();
for(int i = 0;i < list.size();i++)
tempList.add(list.get(i));
Collections.sort(tempList);
for(int i = 0;i < tempList.size();i++) {
char temp = (char) ('A' + tempList.get(i));
System.out.print(temp+" ");
}
System.out.println();
}
step++;
dfs(step);
list.remove(list.size() - 1);
}
}
public static void main(String[] args) {
Main test = new Main();
test.dfs(0);
}
}