D-City(HDU4496)

D-City

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65535/65535 K (Java/Others)
Total Submission(s): 2448    Accepted Submission(s): 862

Problem Description

Luxer is a really bad guy. He destroys everything he met. 
One day Luxer went to D-city. D-city has N D-points and M D-lines. Each D-line connects exactly two D-points. Luxer will destroy all the D-lines. The mayor of D-city wants to know how many connected blocks of D-city left after Luxer destroying the first K D-lines in the input. 
Two points are in the same connected blocks if and only if they connect to each other directly or indirectly.

 

Input

First line of the input contains two integers N and M. 
Then following M lines each containing 2 space-separated integers u and v, which denotes an D-line. 
Constraints: 
0 < N <= 10000 
0 < M <= 100000 
0 <= u, v < N. 

 

Output

Output M lines, the ith line is the answer after deleting the first i edges in the input.

 

Sample Input

5 10 0 1 1 2 1 3 1 4 0 2 2 3 0 4 0 3 3 4 2 4

 

Sample Output

1 1 1 2 2 2 2 3 4 5
Hint
The graph given in sample input is a complete graph, that each pair of vertex has an edge connecting them, so there's only 1 connected block at first. The first 3 lines of output are 1s  because  after  deleting  the  first  3  edges  of  the  graph,  all  vertexes  still  connected together. But after deleting the first 4 edges of the graph, vertex 1 will be disconnected with other vertex, and it became an independent connected block. Continue deleting edges the disconnected blocks increased and finally it will became the number of vertex, so the last output should always be N. 

这个题的意思是给你一个联通块，然后就给你若干条边进行切断，没切断一条边输出其切断后的联通块。

这个题需要用到并查集的faA与faB是否相等来判断其是否会划分为联通块的个数，必须来进行倒着进行处理这些数据。

#include<stdio.h>
#include<string.h>
#include<stack>
using namespace std;
int n,m;
int father[10010];
int find(int x)
{
int a=x;
while(x!=father[x])
{
x=father[x];
}
while(a!=father[a])
{
int z=a;
a=father[a];
father[z]=x;
}
return x;
}
int Union(int a,int b)
{
int faA=find(a);
int faB=find(b);
if(faA!=faB)
{
father[faA]=faB;
return 1;
}
else
return 0;
}
int main()
{
int a[100010],b[100010];
while(scanf("%d%d",&n,&m)!=EOF)
{
stack<int > q;
if(n==0&&m==0)
break;
for(int i=0;i<=n;i++)
{
father[i]=i;
}

int flag;
q.push(n);
for(int i=0;i<m;i++)
{
scanf("%d%d",&a[i],&b[i]);
}
for(int i=m-1;i>0;i--)
{
int flag=Union(a[i],b[i]);
if(flag==1)
n--;
q.push(n);
}
while(!q.empty())
{
printf("%d\n",q.top());
q.pop();
}
}
}