1、測試代碼
#include <iostream>
using namespace std;
int g_loop = 0; /* 循環計數 */
int g_move = 0; /* 數據移動次數 */
void output_info(int *buff,int len, int flag)
{
int i;
if(0 == flag)
{
cout << "before: ";
}
else
{
cout << "after: ";
}
for(i = 0; i < len; ++i)
{
cout << *(buff + i) << " ";
}
cout << endl;
}
/* 獲取一個數的倒數第i位數字 */
int get_num(int num, int i)
{
int temp;
int base = 1;
if(i <= 0)
{
return num;
}
while (--i)
{
base *= 10;
}
return num / base % 10;
}
void clean_barrel(int arr[],int **barrel,int pos[])
{
int i,j,k;
k = 0;
for ( i = 0; i < 10; ++i)
{
for ( j = 0; j < pos[i]; ++j)
{
arr[k++] = barrel[i][j];
}
pos[i] = 0;
}
}
/* 基數排序 */
void radix_sort(int arr[], int len)
{
int max;
int min;
int i,j;
int temp;
int width = 1;
int *barrel[10]; /* 桶指針 */
int pos[10] = {0}; /* 保存數組索引值 */
max = min = arr[0];
for(i = 1; i < len; ++i)
{
if(arr[i] > max)
{
max = arr[i];
}
if(arr[i] < min)
{
min = arr[i];
}
}
cout << "min=" << min << endl;
cout << "max=" << max << endl;
/* 計算最大數位數 */
while (max / 10)
{
++width;
max /= 10;
}
cout << "width=" << width << endl;
// 創建10個桶
for(i = 0; i < 10; ++i)
{
barrel[i] = new int[len]();
}
// 進行每一趟的排序，從個位數開始排
for (i = 1; i <= width; ++i)
{
cout << "=====================" << endl;
cout << "bit=" << i << endl;
for (j = 0; j < len; ++j)
{
++g_loop;
// 獲取倒數第 i 位數
temp = get_num(arr[j], i);
barrel[temp][pos[temp]++] = arr[j];
cout << "bucket=" << temp << " pos="<< pos[temp] << endl;
output_info(barrel[temp], len, 1);
cout << endl;
}
// 取出桶中的數據放回原數組
cout << "==loop " << i << endl;
output_info(arr, len, 0);
clean_barrel(arr,barrel,pos);
output_info(arr, len, 1);
cout << endl;
}
// 釋放桶資源
for(i = 0; i < 10; ++i)
{
delete[] barrel[i];
}
}
int main(void)
{
int array[10]= {20,190,18,1700,151,15,4,13,10,1};
int len = sizeof(array) / sizeof(array[0]);
radix_sort(array, len);
cout << endl;
output_info(array, len, 1);
cout << "move=" << g_move << endl;
cout << "loop=" << g_loop << endl;
return 0;
}
2、測試log
min=1
max=1700
width=4
=====================
bit=1
bucket=0 pos=1
after: 20 0 0 0 0 0 0 0 0 0
bucket=0 pos=2
after: 20 190 0 0 0 0 0 0 0 0
bucket=8 pos=1
after: 18 0 0 0 0 0 0 0 0 0
bucket=0 pos=3
after: 20 190 1700 0 0 0 0 0 0 0
bucket=1 pos=1
after: 151 0 0 0 0 0 0 0 0 0
bucket=5 pos=1
after: 15 0 0 0 0 0 0 0 0 0
bucket=4 pos=1
after: 4 0 0 0 0 0 0 0 0 0
bucket=3 pos=1
after: 13 0 0 0 0 0 0 0 0 0
bucket=0 pos=4
after: 20 190 1700 10 0 0 0 0 0 0
bucket=1 pos=2
after: 151 1 0 0 0 0 0 0 0 0
==loop 1
before: 20 190 18 1700 151 15 4 13 10 1
after: 20 190 1700 10 151 1 13 4 15 18
=====================
bit=2
bucket=2 pos=1
after: 20 0 0 0 0 0 0 0 0 0
bucket=9 pos=1
after: 190 0 0 0 0 0 0 0 0 0
bucket=0 pos=1
after: 1700 190 1700 10 0 0 0 0 0 0
bucket=1 pos=1
after: 10 1 0 0 0 0 0 0 0 0
bucket=5 pos=1
after: 151 0 0 0 0 0 0 0 0 0
bucket=0 pos=2
after: 1700 1 1700 10 0 0 0 0 0 0
bucket=1 pos=2
after: 10 13 0 0 0 0 0 0 0 0
bucket=0 pos=3
after: 1700 1 4 10 0 0 0 0 0 0
bucket=1 pos=3
after: 10 13 15 0 0 0 0 0 0 0
bucket=1 pos=4
after: 10 13 15 18 0 0 0 0 0 0
==loop 2
before: 20 190 1700 10 151 1 13 4 15 18
after: 1700 1 4 10 13 15 18 20 151 190
=====================
bit=3
bucket=7 pos=1
after: 1700 0 0 0 0 0 0 0 0 0
bucket=0 pos=1
after: 1 1 4 10 0 0 0 0 0 0
bucket=0 pos=2
after: 1 4 4 10 0 0 0 0 0 0
bucket=0 pos=3
after: 1 4 10 10 0 0 0 0 0 0
bucket=0 pos=4
after: 1 4 10 13 0 0 0 0 0 0
bucket=0 pos=5
after: 1 4 10 13 15 0 0 0 0 0
bucket=0 pos=6
after: 1 4 10 13 15 18 0 0 0 0
bucket=0 pos=7
after: 1 4 10 13 15 18 20 0 0 0
bucket=1 pos=1
after: 151 13 15 18 0 0 0 0 0 0
bucket=1 pos=2
after: 151 190 15 18 0 0 0 0 0 0
==loop 3
before: 1700 1 4 10 13 15 18 20 151 190
after: 1 4 10 13 15 18 20 151 190 1700
=====================
bit=4
bucket=0 pos=1
after: 1 4 10 13 15 18 20 0 0 0
bucket=0 pos=2
after: 1 4 10 13 15 18 20 0 0 0
bucket=0 pos=3
after: 1 4 10 13 15 18 20 0 0 0
bucket=0 pos=4
after: 1 4 10 13 15 18 20 0 0 0
bucket=0 pos=5
after: 1 4 10 13 15 18 20 0 0 0
bucket=0 pos=6
after: 1 4 10 13 15 18 20 0 0 0
bucket=0 pos=7
after: 1 4 10 13 15 18 20 0 0 0
bucket=0 pos=8
after: 1 4 10 13 15 18 20 151 0 0
bucket=0 pos=9
after: 1 4 10 13 15 18 20 151 190 0
bucket=1 pos=1
after: 1700 190 15 18 0 0 0 0 0 0
==loop 4
before: 1 4 10 13 15 18 20 151 190 1700
after: 1 4 10 13 15 18 20 151 190 1700
after: 1 4 10 13 15 18 20 151 190 1700
move=0
loop=40
3、算法分析
- 非原地排序算法；
- 穩定排序算法；
- 空間複雜度 O（n+k）；
- 時間複雜度 O（kn）。
