如:输出
1 8 7
2 9 6
3 4 5
我的思路:
遍历一圈看成一趟:用变量count 表示那么tripnum从 0,到 (n-1)/2
设置4个变量 ,left,right,up,down 并初始化
代码如下,很简单
#include<iostream>
#include<iomanip>
using namespace std;
#define N 10
void main()
{
int tripnum=0,n=10,count=1,len;
int data[N][N];
int left=0,right=n-1,up=0,down=n-1;
for(;tripnum<(n+1)/2;tripnum++)
{
len=n-2*tripnum;
for(int i=0;i<len;i++)
data[left+i][up]=count++;
for(i=1;i<len;i++)
data[right][up+i]=count++;
for(i=1;i<len;i++)
data[right-i][down]=count++;
for(i=1;i<len-1;i++)
data[left][down-i]=count++;
left++;
up++;
right--;
down--;
}
for(int i=0;i<n;i++)
{
for(int j=0;j<n;j++)
cout<<setw(5)<<data[i][j];
cout<<endl;
}
}
快速排序算法:
#include<iostream>
using namespace std;
void PartitionSort(int a[],int begin, int end)
{
int left = begin;
int right = end;
int temp = a[left];
if ( begin >= end) //设定结束标记
return ;
while(left<right)
{
while( left < right && a[right] >= temp) right--;
a[left] = a[right];
while(left < right && a[left] < temp ) left++;
a[right] = a[left];
}
a[left] = temp;
PartitionSort(a,begin,left-1);
PartitionSort(a,left+1,end);
}
void QuickSort(int a[],int len)
{
PartitionSort(a,0,len-1);
}
void main()
{
int a[]={2,3,1,4,5,3,4,5,6,7};
QuickSort(a, 10);
for(int i=0;i<10;i++)
cout<<a[i]<<" ";
cout<<endl;
}
基于快排选取最小的4的数
#include<iostream>
using namespace std;
void PartitionSort(int a[],int k, int begin, int end)
{
int left = begin;
int right = end;
int temp = a[left];
if ( begin > k || k > end) //设定结束标记
return ;
while(left<right)
{
while( left < right && a[right] >= temp) right--;
a[left] = a[right];
while(left < right && a[left] < temp ) left++;
a[right] = a[left];
}
a[left] = temp;
PartitionSort(a,k,begin,left-1);
PartitionSort(a,k,left+1,end);
}
void QuickSort(int a[],int k, int len)
{
PartitionSort(a,k,0,len-1);
}
void main()
{
int a[]={2,3,1,4,5,3,4,5,6,7};
QuickSort(a, 4,10);
for(int i=0;i<4;i++)
cout<<a[i]<<" ";
cout<<endl;
}