八皇后问题的相关C++代码解答示例

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
#define EIGHT 8
 
struct result
{
  int total;
  int num[10];
};
 
int wzyindex, column[10];
struct result results[100];
 
/**
 * Description:预处理八皇后的下标数组
 */
void pre_prosess(int n)
{
  int i;
 
  for (i = 1; i <= n; i ++) {
    column[i] = i;
  }
}
 
/**
 * Description:column数组数字交换
 */
void swap(int begin, int k)
{
  int temp;
 
  temp = column[begin];
  column[begin] = column[k];
  column[k] = temp;
}
 
/**
 * Description:防止全排列出现重复数据
 */
int check_swap(int begin, int k)
{
  int i;
  for (i = begin; i < k; i ++) {
    if (column[i] == column[k]) {
      return 0;
    }
  }
  return 1;
}
 
int is_eightqueue(int n)
{
  int i, j;
  for (i = 1; i <= n; i ++) {
    for (j = i + 1; j <= n; j ++) {
      if (i - j == column[i] - column[j] || i - j == column[j] - column[i])
        return 0;
    }
  }
  return 1;
}
 
void permutation_queue(int begin, int end)
{
  int k, total;
  if (begin == end) { // 检查八皇后排列正确性
    if (is_eightqueue(end)) {
      for (k = 1, total = 0; k <= end; k ++) {
        total = 10 * total + column[k];
        results[wzyindex].num[k] = column[k]; 
      }
      results[wzyindex].total = total;
      wzyindex ++;
    }
  } else {  // 全排列
    for (k = begin; k <= end; k ++) {
      if (check_swap(begin, k)) { // 保证无重复的全排列
        swap(begin, k);
        permutation_queue(begin + 1, end);
        swap(begin, k);
      }  
    }
  }
}
 
int compare(const void *p, const void *q)
{
  const struct result *a = p;
  const struct result *b = q;
 
  return a->total - b->total;
}
 
int main()
{
  int i, n, m;
  pre_prosess(EIGHT);
  wzyindex = 0;
  permutation_queue(1, EIGHT);
  qsort(results, wzyindex, sizeof(results[0]), compare);
  while (scanf("%d", &n) != EOF) {
    while (n --) {
      scanf("%d", &m);
      m -= 1;
      for (i = 1; i <= EIGHT; i ++) {
        printf("%d", results[m].num[i]);
      }
      printf("\n");
    }
  }
 
  return 0;
}

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>
 
#define N 8
 
typedef struct point {
  int x, y;
} point;
point pts[N];
 
typedef struct string {
  char str[N + 1];
} string;
string strs[93];
 
int windex, count;
 
int isOk(int x, int y)
{
  int i, flag = 1;
 
  for (i = 0; i < count; i ++) {
    if (pts[i].y == y || abs(y - pts[i].y) == abs(x - pts[i].x)) {
      flag = 0;
      break;
    }
  }
 
  return flag;
}
 
void bfsEight(int level)
{
  int i;
 
  if (level > N) {
    for (i = 0; i < N; i ++) {
      strs[windex].str[i] = pts[i].y + '0';
    }
    strs[windex].str[i] = '\0';
    windex ++;
  } else {
    point t;
    for (i = 1; i <= N; i ++) {
      t.x = level;
      t.y = i;
 
      if (isOk(t.x, t.y)) {
        pts[count ++] = t;
        bfsEight(level + 1);
        count -= 1;
      }
    }
  }
}
 
int cmp(const void *p, const void *q)
{
  const string *a = p;
  const string *b = q;
 
  return strcmp(a->str, b->str);
}
 
int main(void)
{
  int n, num;
 
  count = windex = 0;
 
  bfsEight(1);
  qsort(strs, count, sizeof(strs[0]), cmp);
 
  scanf("%d", &n);
 
  while (n --) {
    scanf("%d", &num);
 
    printf("%s\n", strs[num - 1].str);
  }
 
  return 0;
}