Fast sorting (solving small file Division)

# Include <iostream> # include <cstdlib> # define M 20 using namespace std; static int count_insert = 0; static int count_partion = 0; void swap (int & small, int & big) {int temp = small; small = big; big = temp;}/* | insert sort in brief: | cur = 1-> right is the part to be sorted, pre indicates the sorted part. | First store the first position element arr [cur] into tmp, then compare the arr [pre] and arr [cur], | if arr [cur] <arr [pre] is to be sorted, arr [pre + 1] = arr [pre] is shifted. | the purpose of the shift is to shift small elements, here, arr [cur] is placed in the proper position of the sorted part. | in this way, each arr [cur] will be overwritten by arr [pre, this is why tmp = arr [cur] was just started | then place tmp at the location of arr [pre] */void insert_sort (int arr [], int left, int right) {int tmp, cur, pre; for (cur = 1; cur <right; cur ++) {pre = cur-1; tmp = arr [cur]; while (tmp <arr [pre] & pre> = 0) {arr [pre + 1] = ar R [pre]; pre --;} arr [pre] = tmp;} count_insert + = 1;} int partion (int arr [], int left, int right) {int base = arr [right]; int I = left-1; for (int j = left; j <right; j ++) {if (arr [j] <base) {I + = 1; if (arr [j]! = Arr [I]) swap (arr [j], arr [I]);} swap (arr [right], arr [I + 1]); count_partion + = 1; return I + 1;}/* | if the length of the sub-file after division is less than 20, insert and sort the sub-files, | otherwise, quick sorting */void quick_sort (int arr [], int left, int right) {if (left <right) {if (right-left) <= M) insert_sort (arr, left, right); else {int sec = partion (arr, left, right); quick_sort (arr, left, sec-1); quick_sort (arr, sec + 1, right) ;}}int main () {const int size = 500; int s [size]; srand (0); for (int I = 0; I <size; I ++) s [I] = rand () % 200; quick_sort (s, 0, size-1); for (I = 0; I <size; I ++) cout <s [I] <"; cout <endl; cout <" call insert_sort "<count_insert <" times "<endl; cout <"call partion_sort" <count_partion <"times" <endl; cin. get (); return 0 ;}