ZOJ Problem Set - 1171 Sorting the Photos

ZOJ Problem Set - 1171

Sorting the Photos

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Time Limit: 2 Seconds                                     Memory Limit: 65536 KB                            

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Imagine you have a pile of 1 <= N <= 10^5 photos. Some of them are faced   upwards and the others faced downwards. Your goal is to sort them so all the   photos are faced the same direction. The only operation you are allowed to do   is to take any amount of the photos from the top into the separate pile, turn   that pile upside-down as the whole and put it back over the rest of original   pile.

  Write the program that calculates the minimum number of such operations needed   to complete the sorting goal.

This problem contains multiple test cases!

The first line of a multiple input is an integer N, then a blank line followed   by N input blocks. Each input block is in the format indicated in the problem   description. There is a blank line between input blocks.

The output format consists of N output blocks. There is a blank line between   output blocks.

Input

  First line of the input contains the only number. Then, characters going possibly   separated by newline and/or space characters "D" - faced down or "U"   - faced up.

Output

  Single integer number - minimal number of flip operations required to sort the   photos pile.

Sample Input

  1

5
  UU D
  UU

Sample Output

  2

AC代码：

#include<iostream>
#include<stdio.h>
using namespace std;
int main()
{
	int cas;
	cin>>cas;
	while(cas--)
	{
		int n;
		cin>>n;
		char *pt=new char[n];
		for(int i=0;i<n;i++)cin>>pt[i];
		char tag=pt[0];
		int count=0;
		for(int i=1;i<n;i++)
		{
			if(tag!=pt[i])
			{
				tag=pt[i];
				count++;
			}
		}
		cout<<count<<endl;
		if(cas!=0)cout<<endl;
	} 
}