HDU4496_D-City (and query set edge/reverse)

D-City Time Limit: 2000/1000 MS (Java/others) memory limit: 65535/65535 K (Java/Others)
Total submission (s): 1315 accepted submission (s): 496


Problem descriptionluxer 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.
Inputfirst 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.
 
Outputoutput 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 5HintThe 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.  

 
Source2013 ACM-ICPC Jilin Tonghua national invitational Competition -- The problem reproduction problem solving report given a map, N points, M side, find in order to delete the remaining after the side of the UNICOM block. In general, we use and query sets to add edges. You can also use and query sets to delete the edge. Deleting 1st edges equals M-1 edge...

#include <iostream>#include <cstdio>#include <cstring>#define M 100000+10#define N 10000+10using namespace std;int n,m;struct node{    int u,v;} edge[M];int B[N],ans[M];int fine(int x){    if(B[x]!=x)    B[x]=fine(B[x]);    return B[x];}int main(){    int i;    while(~scanf("%d%d",&n,&m))    {    memset(ans,0,sizeof(ans));    memset(edge,0,sizeof(edge));        for(i=0;i<n;i++)        B[i]=i;        for(i=0; i<m; i++)        {            scanf("%d%d",&edge[i].u,&edge[i].v);        }        int sum=n;        for(i=m-1;i>=0;i--)        {            ans[i]=sum;            int xx=fine(edge[i].u);            int yy=fine(edge[i].v);            if(xx!=yy)            {                sum--;                B[xx]=yy;            }        }        for(i=0;i<m;i++)        printf("%d\n",ans[i]);    }    return 0;}