Bubble Sort

Question

Write a program of the Bubble Sort algorithm which sorts a sequence A in ascending order. The algorithm should be based on the following pseudocode:

BubbleSort(A)
1 for i = 0 to A.length-1
2     for j = A.length-1 downto i+1
3         if A[j] < A[j-1]
4             swap A[j] and A[j-1]

Note that, indices for array elements are based on 0-origin.

Your program should also print the number of swap operations defined in line 4 of the pseudocode.

Input

The first line of the input includes an integer N, the number of elements in the sequence.

In the second line, N elements of the sequence are given separated by spaces characters.

Output

The output consists of 2 lines.

In the first line, please print the sorted sequence. Two contiguous elements of the sequence should be separated by a space character.

In the second line, please print the number of swap operations.

Constraints

1 ≤ N ≤ 100

Sample Input 1

5

5 3 2 4 1

Sample Output 1

1 2 3 4 5

8

Sample Input 2

6

5 2 4 6 1 3

Sample Output 2

1 2 3 4 5 6

9

Meaning

实现冒泡排序的过程

Solution

第一层for循环仅仅是为了执行n次循环，然后第二层循环中，从最后一个元素开始，如果比前面的元素小那么就实现交换。这样一层执行完毕，第一个数一定是最小的了。

Coding

#if 1
#include<iostream>
using namespace std;
void BubbleSort(int a[], int n, int &sum) {
	int i, j;
	for ( i = 0; i < n; i++){
		for (j = n - 1; j > i; j--) {
			if (a[j] < a[j - 1])
			{
				swap(a[j], a[j - 1]);
				sum++;
			}
		}
	}
}
void Print(int a[], int n) {
	for (int i = 0; i < n; i++) {
		if (i > 0) cout << " ";
		cout << a[i];
	}
}
int main() {
	int n,sum=0;
	cin >> n;
	int a[105];
	for (int i = 0; i < n; i++)
		cin >> a[i];
	BubbleSort(a, n, sum);
	Print(a, n);
	cout << endl << sum <<endl;
	
}
#endif

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