（C语言）构造n阶幻方

（C语言）构造$n$阶幻方

$n$阶幻方分奇、单偶和双偶型。具体可见下面的博客：
https://blog.youkuaiyun.com/html5gz/article/details/4804170

代码：（附赠一个check函数用于检查构造出来的是不是幻方）

#include <stdio.h>
int ans[1005][1005];
void create(int n, int (*square)[n]);
void out(int n, int (*square)[n]);
int check(int n, int (*square)[n]);
void clear(int n, int (*square)[n]);
int main(){
  int n;
  scanf("%d", &n);
  create(n, ans);
  out(n, ans);
}
void create(int n,int (*square)[n]){
  if(n%2==1){
    int i = 0;
    int j = (n - 1) / 2;
    int ii, jj;
    int step = 1;
    square[i][j] = step;
    while(step<n*n){
      ii = (i - 1 + n) % n;
      jj = (j + 1) % n;
      if(square[ii][jj]==0){
        i = ii;
        j = jj;
        square[i][j] = ++step;
      }
      else{
        i = i + 1;
        square[i][j] = ++step;
      }
    }
  }
  else{
    if(n%4==0){
      int i,j;
      int step = 1;
      for (i = 0; i < n;i++){
        for (j = 0; j < n;j++){
          square[i][j] = step++;
        }
      }
      int k;
      int m = n / 4;
      for (k = 0; k < m;k++){
        for (i = 0; i < m;i++){
          square[4 * k][4 * i] = n * n + 1 - square[4 * k][4 * i];
          square[4 * k][4 * i + 3] = n * n + 1 - square[4 * k][4 * i + 3];
          square[4 * k + 3][4 * i] = n * n + 1 - square[4 * k + 3][4 * i];
          square[4 * k + 3][4 * i + 3] = n * n + 1 - square[4 * k + 3][4 * i + 3];
          square[4 * k + 1][4 * i + 1] = n * n + 1 - square[4 * k + 1][4 * i + 1];
          square[4 * k + 1][4 * i + 2] = n * n + 1 - square[4 * k + 1][4 * i + 2];
          square[4 * k + 2][4 * i + 1] = n * n + 1 - square[4 * k + 2][4 * i + 1];
          square[4 * k + 2][4 * i + 2] = n * n + 1 - square[4 * k + 2][4 * i + 2];
        }
      }
    }
    else if(n%4==2){
      int m = n / 2;
      int i,j;
      int temp[m][m];
      for (i = 0;i < m;i++){
        for (j = 0; j < m;j++){
          temp[i][j] = 0;
        }
      }
      create(m, temp);
      for (i = 0; i < m;i++){
        for (j = 0; j < m;j++){
          square[i][j] = temp[i][j];
          square[i][j + m] = temp[i][j] + 2 * m * m;
          square[i + m][j] = temp[i][j] + 3 * m * m;
          square[i + m][j + m] = temp[i][j] + m * m;
        }
      }
      int k = (n - 2) / 4;
      int mm = (m - 1) / 2;
      int t;
      for (i = 0; i < mm;i++){
        for (j = 0; j < k;j++){
          t = square[i][j];
          square[i][j] = square[i + m][j];
          square[i + m][j] = t;
        }
      }
      for (j = 0; j < k;j++){
        t = square[mm][mm + j];
        square[mm][mm + j] = square[mm + m][mm + j];
        square[mm + m][mm + j] = t;
      }
      for (i = mm + 1; i < m;i++){
        for (j = 0; j < k;j++){
          t = square[i][j];
          square[i][j] = square[i + m][j];
          square[i + m][j] = t;
        }
      }
      for (j = n - mm - 1; j >= n - mm - k + 1;j--){
        for (i = 0; i < m;i++){
          t = square[i][j];
          square[i][j] = square[i + m][j];
          square[i + m][j] = t;
        }
      }
    }
  }
}

void out(int n, int (*square)[n]){
  int i,j;
  for (i = 0; i < n;i++){
    for (j = 0; j < n;j++){
      printf(" %4d", square[i][j]);
    }
    printf("\n");
  }
}

int check(int n,int (*square)[n]){
  int s = (n * (n * n + 1)) / 2;
  int sum = 0;
  int i,j;
  for (i = 0; i < n;i++){
    sum = 0;
    for (j = 0; j < n;j++){
      sum += square[i][j];
      if(sum>s){
        return 0;
      }
    }
    if(sum!=s){
      return 0;
    }
  }
  for (j = 0; j < n;j++){
    sum = 0;
    for (i = 0; i < n;i++){
      sum += square[i][j];
      if(sum>s){
        return 0;
      }
    }
    if(sum!=s){
      return 0;
    }
  }
  sum = 0;
  i = j = 0;
  while(i<n&&j<n){
    sum += square[i][j];
    i++;
    j++;
    if(sum>s){
      return 0;
    }
  }
  if(sum!=s){
    return 0;
  }
  sum = 0;
  i=0;
  j = n - 1;
  while(i<n&&j>=0){
    sum += square[i][j];
    i++;
    j--;
    if(sum>s){
      return 0;
    }
  }
  if(sum!=s){
    return 0;
  }
  return 1;
}

void clear(int n,int (*square)[n]){
  int i, j;
  for (i = 0; i < n;i++){
    for (j = 0;j<n;j++){
      square[i][j] = 0;
    }
  }
}