void swap(int& x, int& y)
{ int temp = x; x =
y; y = temp; }
int min_position(vector<int>& a,
int from, int to)
{
int min_pos = from;
int i;
for (i = from + 1; i <=
to; i++)
if
(a[i] < a[min_pos]) min_pos = i;
return min_pos;
}
void selection_sort(vector<int>&
a)
{
int next; /* the next position
to be set to the minimum */
for (next = 0; next < a.size()
- 1; next++)
{ /* find the position
of the minimum */
int min_pos
= min_position(a, next, a.size() - 1);
if (min_pos
!= next)
swap(a[min_pos], a[next]);
}
}
void print(vector<int> a)
{
int i;
for (i = 0; i < a.size();
i++) cout << a[i] << " ";
cout << "\n";
}
void rand_seed()
{
int seed = static_cast<int>(time(0));
srand(seed);
}
int rand_int(int a, int b)
{ return a + rand() % (b - a + 1);
}
int main()
{
rand_seed();
vector<int> v(20);
int i;
for (i = 0; i < v.size();
i++)
v[i] = rand_int(1, 100);
print(v);
selection_sort(v);
print(v);
return 0;
}
Измерване на времето за работа и анализ на ефективността на алгоритъма за сортиране чрез селекция
// sorttime.cpp
#include <iostream>
#include <vector>
#include <cstdlib>
#include <ctime>
using namespace std;
#include "ccc_time.cpp"
void swap(int& x, int& y)
{ int temp = x; x =
y; y = temp; }
int min_position(vector<int>& a,
int from, int to)
{
int min_pos = from;
int i;
for (i = from + 1; i <=
to; i++)
if
(a[i] < a[min_pos]) min_pos = i;
return min_pos;
}
void selection_sort(vector<int>&
a)
{
int next;
for (next = 0; next <
a.size() - 1; next++)
{
int min_pos
= min_position(a, next, a.size() - 1);
if (min_pos
!= next) swap(a[min_pos], a[next]);
}
}
void rand_seed()
/* PURPOSE: Set the seed of the random
number generator
*/
{ int seed = static_cast<int>(time(0));
srand(seed);
}
int rand_int(int a, int b)
{ return a + rand() % (b - a + 1);
}
int main()
{
rand_seed();
cout << "Enter vector
size: ";
int n;
cin >> n;
vector<int> v(n);
int i;
for (i = 0; i < v.size();
i++) v[i] = rand_int(1, 100);
Time before;
selection_sort(v);
Time after;
cout << "Elapsed time
= " << after.seconds_from(before)
<< " seconds\n";
return 0;
}
Сортиране
чрез сливане
// mergesort.cpp
#include <iostream>
#include <vector>
#include <cstdlib>
#include <ctime>
using namespace std;
void merge(vector<int>& a, int from,
int mid, int to)
{
int n = to - from + 1; /*
size of the range to be merged */
/* merge both halves into a temporary
vector b */
vector<int> b(n);
int i1 = from;
/* next element to consider in the first
half */
int i2 = mid + 1;
/* next element to consider in the second
half */
int j = 0; /* next open position
in b */
/* as long as neither i1 nor i2 past the
end, move the smaller element into b */
while (i1 <= mid &&
i2 <= to)
{ if (a[i1] < a[i2])
{ b[j] = a[i1]; i1++; }
else
{ b[j] = a[i2]; i2++; }
j++;
}
/* note that only one of the two while
loops below is executed */
/* copy any remaining entries of the first
half */
while (i1 <= mid)
{ b[j] = a[i1]; i1++;
j++; }
/* copy any remaining entries of the second
half */
while (i2 <= to)
{ b[j] = a[i2]; i2++;
j++; }
/* copy back from the temporary vector
*/
for (j = 0; j < n; j++)
a[from + j] = b[j];
}
void merge_sort(vector<int>& a,
int from, int to)
{
if (from == to) return;
int mid = (from + to) / 2;
/* sort the first and the second half
*/
merge_sort(a, from, mid);
merge_sort(a, mid + 1, to);
merge(a, from, mid, to);
}
void print(vector<int> a)
{
int i;
for (i = 0; i < a.size();
i++) cout << a[i] << " ";
cout << "\n";
}
void rand_seed()
{
int seed = static_cast<int>(time(0));
srand(seed);
}
int rand_int(int a, int b)
{ return a + rand() % (b - a + 1);
}
int main()
{
rand_seed();
vector<int> v(20);
int i;
for (i = 0; i < v.size();
i++)
v[i] =
rand_int(1, 100);
print(v);
merge_sort(v, 0, v.size()
- 1);
print(v);
return 0;
}
Анализ на алгоритъма за сортиране чрез сливане
Търсене в
несортирани и сортирани данни
// lsearch.cpp
#include <iostream>
#include <vector>
#include <cstdlib>
#include <ctime>
using namespace std;
int linear_search(vector<int> v, int
a)
{
int i;
for (i = 0; i < v.size();
i++)
if
(v[i] == a) return i;
return -1;
}
void print(vector<int> a)
{
int i;
for (i = 0; i < a.size();
i++) cout << a[i] << " ";
cout << "\n";
}
void rand_seed()
{
int seed = static_cast<int>(time(0));
srand(seed);
}
int rand_int(int a, int b)
{ return a + rand() % (b - a + 1);
}
int main()
{
rand_seed();
vector<int> v(20);
int i;
for (i = 0; i < v.size();
i++) v[i] = rand_int(1, 100);
print(v);
cout << "Enter number
to search for: ";
int n;
cin >> n;
int j = linear_search(v,
n);
cout << "Found in position
" << j << "\n";
return 0;
}