厦门网站推广步骤机构/代发关键词包收录
[Java] 纯文本查看 复制代码import java.util.List;
import java.util.ArrayList;
/**
* □ + □ = □
* □ - □ = □
* □ * □ = □
* □ / □ = □
*
* 将 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13 填入上面方框，不能重复使用，使等式成立。
*
*
* @author 1234
*
*/
public class _dfs深搜01 {
static boolean[] flags = new boolean[14];
static boolean[] fuhao = new boolean[4]; // +-*/
static List> result = new ArrayList<>();
public static void dfs(ArrayList arr) {
if (arr.size() == 12) {
System.out.println("in " + arr);
List arr1 = new ArrayList<>();
arr1.addAll(arr);
result.add((ArrayList) arr1);
return;
}
for (int i = 1; i <= 13; i++) {
if (!flags[i] && i != 11) {
flags[i] = true;
for (int j = 1; j <= 13; j++) {
if (!flags[j] && i != 11) {
flags[j] = true;
if (!fuhao[0] && i + j <= 13&& !flags[i+j]) {
fuhao[0] = true;
flags[i+j] = true;
arr.add(i);
arr.add(j);
arr.add(i+j);
dfs(arr);
arr.remove(new Integer(i));
arr.remove(new Integer(j));
arr.remove(new Integer(i + j));
fuhao[0] = false;
flags[i+j] = false;
}
if (fuhao[0] && !fuhao[1] && i - j > 0 && !flags[i-j]) {
fuhao[1] = true;
flags[i-j] = true;
arr.add(i);
arr.add(j);
arr.add(i-j);
dfs(arr);
arr.remove(new Integer(i));
arr.remove(new Integer(j));
arr.remove(new Integer(i-j));
fuhao[1] = false;
flags[i-j] = false;
}
if (fuhao[0] && fuhao[1] && !fuhao[2] && i * j <= 13&& !flags[i*j]) {
fuhao[2] = true;
flags[i*j] = true;
arr.add(i);
arr.add(j);
arr.add(i*j);
dfs(arr);
arr.remove(new Integer(i));
arr.remove(new Integer(j));
arr.remove(new Integer(i*j));
fuhao[2] = false;
flags[i*j] = false;
}
if (fuhao[0] && fuhao[1] && fuhao[2] && !fuhao[3] && i / j > 0 && i % j == 0 && !flags[i/j]) {
fuhao[3] = true;
flags[i/j] = true;
arr.add(i);
arr.add(j);
arr.add(i/j);
dfs(arr);
arr.remove(new Integer(i));
arr.remove(new Integer(j));
arr.remove(new Integer(i/j));
fuhao[3] = false;
flags[i/j] = false;
}
flags[j] = false;
}
}
flags[i] = false;
}
}
return;
}
public static void main(String[] args) {
// TODO 自动生成的方法存根
long startTime = System.currentTimeMillis();
dfs(new ArrayList());
System.out.println(result.size());
System.out.println(result);
System.out.println("共花时: " + (System.currentTimeMillis() - startTime) + " 毫秒");
}
}