思路方法:从M个数中找出最小
个数,放在无序数列最前面.算法正确性是明显.如果有N个数,那么需要N-1轮
搜索.第i次搜索要比较,要比较N-i次比较,则比较次数为:(N-1) + (N-2) + (N-3) + ... + 1 = N(N-1)/2
O(N^2)
#
<stdlib.h>#
<stdio.h>#
<errno.h>#
<time.h>#
MAX_LENGTH 100/*Show usage*/
void usage(char * prog)
{
pr
f(\"%s Usage:\\n\", prog);pr
f(\"%s <the count of numbers to sort (should be less than 100)>\\n\", prog);}
/*Generate and initialize the list*/
* generate_list( count){
i; * list;list = (
*)malloc(count*
());
(list 
NULL){
perror(\"malloc\");
NULL;}
/*Initialize the list with
egers less than 100*/srandom((unsigned
)time(NULL));for (i = 0; i < count ; i
)list[i] = random
%100; list;}
/*Show the list*/
void show_list(
* list, length){
i;for(i = 0; i < length; i
)pr
f(\"%d \", list[i]);pr
f(\"\\n\");}
/*algorithm*/
void select_sort(
* list, length){
i, j, min; temp;for(i = 0; i < length-1; i
){
min = i;
for(j = i +1; j < length; j
){
(list[j] < list[min])min = j;
}
/*Swap the two elements*/
temp = list[min];
list[min] = list[i];
list[i] = temp;
show_list(list, length);
}
}
( argc, char * argv
){
length; * list = NULL;/*Deal with the arguments*/
(argc != 2){
usage(argv[0]);
exit(127);
}
length = atoi(argv[1]);
(!length || length > MAX_LENGTH){
usage(argv[0]);
exit(129);
}
list = generate_list(length);
(list NULL)exit(128);
{
show_list(list, length);
select_sort(list, length);
}
free(list);
1;}
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