輸出魔方陣C語言

 

方法一：全排列之後判斷，複雜度很大，只能測到3階

//全排列（注意回溯），再判斷 
#include<stdio.h>
#include<math.h>
#define N 100
int judge[N][N];
void f(int *a,int n,int m){
	int i,temp,j,k,h,sum1,sum2;
	if(m==n){
		k=1;
		h=sqrt(n);
		for(i=1;i<=h;i++){
			for(j=1;j<=h;j++){
				judge[i][j]=a[k];
				k++;
			}
		}
		for(i=1;i<=h;i++){
			sum1=0;
			sum2=0;
			for(j=1;j<=h;j++){
				sum1+=judge[i][j];
				sum2+=judge[j][i];
			}
			if(i==1)	temp=sum1;
			if(sum1!=sum2||sum1!=temp)	return;
			else	temp=sum1;
		}
		sum1=0;
		sum2=0;
		for(i=1;i<=h;i++){
			sum1+=judge[i][i];
		}	
		for(i=1;i<=h;i++){
			sum2+=judge[i][h-i+1];
		}	
		if(sum1==sum2&&sum1==temp){
			for(i=1;i<=h;i++){
				for(j=1;j<=h;j++){
					printf("%-3d",judge[i][j]);
				}
				putchar('\n');
			}
			putchar('\n');
		}	
		return;
	} 
	for(i=m;i<=n;i++){
		temp=a[m];
		a[m]=a[i];
		a[i]=temp;
		f(a,n,m+1);
		temp=a[m];//回溯 
		a[m]=a[i];
		a[i]=temp;
	} 
}
int main(){
	int n,a[N],i;
	do{
		printf("輸入n：");
		scanf("%d",&n);
	}while((int)sqrt(n)*(int)sqrt(n)!=n);
	for(i=1;i<=n;i++){
		a[i]=i;
	}
	f(a,n,1);
	return 0;
} 

方法一：按規律來，即c語言課後題解析，只能求奇數階

#include<stdio.h>
#define N 100
void f(int (*a)[N],int n){
	int i=0,j=n/2,k;
	int t1,t2;
	a[i][j]=1;
	for(k=2;k<=n*n;k++){
		t1=i--;
		t2=j++; 
		if(i==-1)	i=n-1;
		if(j==n)	j=0;
		if(a[i][j]!=0||(t1==0&&t2==(n-1))){
			i=t1+1;
			j=t2;
			if(i==n)	i=0;
			a[i][j]=k;
		}else if(a[i][j]==0){
			a[i][j]=k;
		}
	}
}
int main(){
	int a[N][N]={0};
	int n,i,j;
	printf("請輸入n：");
	scanf("%d",&n);
	f(a,n);
	for(i=0;i<n;i++){
		for(j=0;j<n;j++){
			printf("%-5d",a[i][j]);
		}
		putchar('\n');
	}
	return 0;
}