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BackTracking.java
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BackTracking.java
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/*
* Copyright (c) 2018. Lorem ipsum dolor sit amet, consectetur adipiscing elit.
* Morbi non lorem porttitor neque feugiat blandit. Ut vitae ipsum eget quam lacinia accumsan.
* Etiam sed turpis ac ipsum condimentum fringilla. Maecenas magna.
* Proin dapibus sapien vel ante. Aliquam erat volutpat. Pellentesque sagittis ligula eget metus.
* Vestibulum commodo. Ut rhoncus gravida arcu.
*/
package com.example.god.androidmore.algorithm.other;
public class BackTracking {
/**
* 八皇后问题_result = 92
* 先获取单列内可放置的集合,递归遍历所有可能的
*/
private static int MAX_QUEEN = 8;
private static int num = 0;
private static int[] allResult = new int[MAX_QUEEN];
public static void queueQuestion() {
getLineQueens(0);
}
public static void getLineQueens(int lineCount) {
boolean[] lineResult = new boolean[MAX_QUEEN];
for (int j = 0; j < lineCount; j++) {
lineResult[allResult[j]] = true;
int x = lineCount - j;
if (allResult[j] - x >= 0) {
lineResult[allResult[j] - x] = true;
}
if (allResult[j] + x < MAX_QUEEN) {
lineResult[allResult[j] + x] = true;
}
}
for (int i = 0; i < MAX_QUEEN; i++) {
if (!lineResult[i]) {
allResult[lineCount] = i;
if (lineCount < MAX_QUEEN - 1) {
getLineQueens(lineCount + 1);
} else {
num++;
printQueen(num, allResult);
}
}
}
}
/**
* 打印结果
*/
static void printQueen(int num, int[] result) {
char[][] results = new char[MAX_QUEEN][MAX_QUEEN];
System.out.print("第" + num + "种排列:\n");
for (int i = 0; i < result.length; i++) {
results[i][result[i]] = 'X';
}
for (int i = 0; i < MAX_QUEEN; i++) {
for (int j = 0; j < MAX_QUEEN; j++) {
if (results[i][j] == 'X') {
System.out.print("X");
} else {
System.out.print("0");
}
}
System.out.print("\n");
}
}
}