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Lesson7_2.java
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94 lines (70 loc) · 2.87 KB
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import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
public class Lesson7_2 {
// 设置齐王的马跑完所需时间
public static HashMap<String, Double> q_horses_time = new HashMap<String, Double>(){
{
put("q1", 1.0);
put("q2", 2.0);
put("q3", 3.0);
}
};
// 设置田忌的马跑完所需时间
public static HashMap<String, Double> t_horses_time = new HashMap<String, Double>(){
{
put("t1", 1.5);
put("t2", 2.5);
put("t3", 3.5);
}
};
// 保存田忌马匹的全排列
public static ArrayList<ArrayList<String>> t_results = new ArrayList<>();
public static ArrayList<ArrayList<String>> q_results = new ArrayList<>();
/**
* @Description: 使用函数的递归（嵌套）调用，找出所有可能的马匹出战顺序
* @param horses-目前还剩多少马没有出战，result-保存当前已经出战的马匹及顺序，all_results-保存所有的全排列
* @return void
*/
public static void permutate(ArrayList<String> horses, ArrayList<String> result, ArrayList<ArrayList<String>> all_results) {
// 所有马匹都已经出战，判断哪方获胜，输出结果
if (horses.size() == 0) {
all_results.add(result);
return;
}
for (int i = 0; i < horses.size(); i++) {
// 从剩下的未出战马匹中，选择一匹，加入结果
ArrayList<String> newResult = (ArrayList<String>)(result.clone());
newResult.add(horses.get(i));
// 将已选择的马匹从未出战的列表中移出
ArrayList<String> rest_horses = ((ArrayList<String>)horses.clone());
rest_horses.remove(i);
// 递归调用，对于剩余的马匹继续生成排列
permutate(rest_horses, newResult, all_results);
}
}
public static void compare(ArrayList<String> t, ArrayList<String> q) {
int t_won_cnt = 0;
for (int i = 0; i < t.size(); i++) {
System.out.println(t_horses_time.get(t.get(i)) + " " + q_horses_time.get(q.get(i)));
if (t_horses_time.get(t.get(i)) < q_horses_time.get(q.get(i))) t_won_cnt ++;
}
if (t_won_cnt > (t.size() / 2)) System.out.println("田忌获胜！");
else System.out.println("齐王获胜！");
System.out.println();
}
public static void main(String[] args) {
ArrayList<String> t_horses = new ArrayList<String>(Arrays.asList("t1", "t2", "t3"));
Lesson7_2.permutate(t_horses, new ArrayList<String>(), t_results);
ArrayList<String> q_horses = new ArrayList<String>(Arrays.asList("q1", "q2", "q3"));
Lesson7_2.permutate(q_horses, new ArrayList<String>(), q_results);
System.out.println(t_results);
System.out.println(q_results);
System.out.println();
for (int i = 0; i < t_results.size(); i++) {
for (int j = 0; j < q_results.size(); j++) {
Lesson7_2.compare(t_results.get(i), q_results.get(j));
}
}
}
}