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:
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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
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
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#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 |
