HDU 5122 求交换的轮数

HOT~ 杭电2015级新生如何加入ACM集训队？

K.Bro Sorting

Time Limit: 2000/2000 MS (Java/Others)    Memory Limit: 512000/512000 K (Java/Others)
Total Submission(s): 1336    Accepted Submission(s): 608

Problem Description

Matt’s friend K.Bro is an ACMer.

Yesterday, K.Bro learnt an algorithm: Bubble sort. Bubble sort will compare each pair of adjacent items and swap them if they are in the wrong order. The process repeats until no swap is needed.

Today, K.Bro comes up with a new algorithm and names it K.Bro Sorting.

There are many rounds in K.Bro Sorting. For each round, K.Bro chooses a number, and keeps swapping it with its next number while the next number is less than it. For example, if the sequence is “1 4 3 2 5”, and K.Bro chooses “4”, he will get “1 3 2 4 5” after this round. K.Bro Sorting is similar to Bubble sort, but it’s a randomized algorithm because K.Bro will choose a random number at the beginning of each round. K.Bro wants to know that, for a given sequence, how many rounds are needed to sort this sequence in the best situation. In other words, you should answer the minimal number of rounds needed to sort the sequence into ascending order. To simplify the problem, K.Bro promises that the sequence is a permutation of 1, 2, . . . , N .

 

Input

The first line contains only one integer T (T ≤ 200), which indicates the number of test cases. For each test case, the first line contains an integer N (1 ≤ N ≤ 10 ⁶).

The second line contains N integers a _i (1 ≤ a _i ≤ N ), denoting the sequence K.Bro gives you.

The sum of N in all test cases would not exceed 3 × 10 ⁶.

 

Output

For each test case, output a single line “Case #x: y”, where x is the case number (starting from 1), y is the minimal number of rounds needed to sort the sequence.

 

Sample Input

2 5 5 4 3 2 1 5 5 1 2 3 4

 

Sample Output

Case #1: 4 Case #2: 1

Hint

In the second sample, we choose “5” so that after the first round, sequence becomes “1 2 3 4 5”, and the algorithm completes.

 

Source

2014ACM/ICPC亚洲区北京站-重现赛（感谢北师和上交）

 

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本题的题意是,n个数中选一个数,让他可以与右边小于他的相邻的数交换位置,一直交换到右边相邻的数大于他为止,算作一圈
看最少可以这样交换几圈

 

#include
#include
#include

using namespace std;

int a[3000100];
int b[3000100];
int main()
{
	int n,T;
	while(~scanf("%d",&T))
	{
		int Case=0;
		while(T--)
		{
			Case++;
			scanf("%d",&n);
			for(int i=0;i=0;i--)//将后面最小数保存
			{
				if(Min>a[i])
				{
					Min=a[i];
					b[i]=Min;
				}
				else
				{
					b[i]=Min;
				}
			}
			int num=0;
			for(int i=0;ib[i])
					num++;
			}
			printf("Case #%d: %d\n",Case,num);
		}
	}
}