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HDOJ1856(More is better)

2009-04-10 21:23 246 查看

More is better

Time Limit: 5000/1000 MS (Java/Others) Memory Limit: 327680/102400 K (Java/Others)
Total Submission(s): 661 Accepted Submission(s): 247


[align=left]Problem Description[/align]
Mr Wang wants some boys to help him with a project. Because the project is rather complex, the more boys come, the better it will be. Of course there are certain requirements.

Mr Wang selected a room big enough to hold the boys. The boy who are not been chosen has to leave the room immediately. There are 10000000 boys in the room numbered from 1 to 10000000 at the very beginning. After Mr Wang's selection any two of them who are still in this room should be friends (direct or indirect), or there is only one boy left. Given all the direct friend-pairs, you should decide the best way.

[align=left]Input[/align]
The first line of the input contains an integer n (0 ≤ n ≤ 100 000) - the number of direct friend-pairs. The following n lines each contains a pair of numbers A and B separated by a single space that suggests A and B are direct friends. (A ≠ B, 1 ≤ A, B ≤ 10000000)

[align=left]Output[/align]
The output in one line contains exactly one integer equals to the maximum number of boys Mr Wang may keep.

[align=left]Sample Input[/align]
4
1 2
3 4
5 6
1 6
4
1 2
3 4
5 6
7 8


[align=left]Sample Output[/align]
4
2

Hint
A and B are friends(direct or indirect), B and C are friends(direct or indirect),
then A and C are also friends(indirect).

In the first sample {1,2,5,6} is the result.
In the second sample {1,2},{3,4},{5,6},{7,8} are four kinds of answers.


一开始用标准并查集做TLE了n次,就是以下代码:

//Time Limit Exceeded 1856 1000MS 78576K 1492 B C++ Xredman
//Time Limit Exceeded 1856 1000MS 78576K 1790 B C++ Xredman
#include <iostream>
#include <map>
using namespace std;

const int N = 10000002;

typedef struct

Node boy
;
int cnt
;
int n, maxb, minb;

void init()

int find(int x)

void merge(int a, int b)

int main()
//Accepted 1856 250MS 78592K 990 B C++ Xredman
#include <iostream>
using namespace std;

const int N = 10000002;

typedef struct

Node boy
;
int n;
int result;

void init()

int find(int x)

void merge(int a, int b)

int main()
{
int a, b, i;
bool flag ;
while(cin>>n)
{
result = 1;
init();
while(n--)
{
scanf("%d%d", &a, &b);
a = find(a);
b = find(b);
if(a != b)
merge(a,b);
}
cout<<result<<endl;
}
return 0;
}
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