冒泡优化

发表于

优化1 没有进行过交换结束
优化2 通过记录最后交换的位置，及终点的位置
优化3 波浪排序+优化1+优化2

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
#if 0
#include<bits/stdc++.h>                       
using namespace std;                      
int a[10000];
int n;
void sort(int a[], int n) {
	bool flag = 0;
	int k = n-1;
	int last;
	for (int i = 0; i < n-1; i++) {
		flag = 0;
		for (int j = 0; j < k; j++) {
			sum++;
			if (a[j] > a[j+1]) {
				flag = 1;
				last = j;
				swap(a[j], a[j+1]);
			}
		}
		if (flag == 0) {
			break;
		}
		k = last;
	}
}
int main()
{
	while(1) {
		sum = 0;
		cin>>n;
		for (int i = 0; i < n; i++) {
			a[i] = rand() % n;
		}		
		sort(a, n);
		for(int i = 0; i < n; i++)
			 cout<<a[i]<<" "; 
	
	}
} 

#endif

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
#if 0                      //波浪排序 就上两种优化
#include<bits/stdc++.h>
using namespace std;
int a[100000],n;
void sort(int a[], int n) {
	int left = 0, right = n-1;
	int flag = 0;
	int last;
	while (left < right) {
		for (int i = left; i < right; i++) {
			sum++;
			if (a[i] > a[i+1]) {
				swap(a[i], a[i+1]);
				flag = 1;
				last = i;
			}
		}
		if (flag == 0) break;
		right = last;
		flag = 0;
		for (int j = last; j > left; j--) {
			sum++;
			if (a[j] < a[j-1]) {
				swap(a[j], a[j-1]);
				flag = 1;
				last = j;
			}
		}
		if (flag == 0) break;
		left = last;
	}
}
int main()
{
	while(1) {
		cin>>n;
		for (int i = 0; i < n; i++) {
			a[i] = rand() % n;
		}		
		sort(a, n);
		for(int i = 0; i < n; i++)
			 cout<<a[i]<<" "; 
	
	}
}  
#endif