Tuesday, 15 March 2016

City and Soldiers

City and Soldiers
Today, King Trophies is on another rampage to destroy the small village controlled by Alex. Please help his soldiers.
At first, there are N individual soldiers, who haven't yet joined together; each of these soldiers is the leader of his/her own group. You have to handle 3 types of operations:
1) Two groups find each other, and the leader of the first group steps down.
2) A becomes leader of his group
3) Output the leader of a certain group
Input:
The first line contains the number N, the number of soldiers, and Q, the number of operations.
The next Q lines contains operations in the following format:
1 a b: Groups containing person a and person b find each other, and the leader of the group containing person asteps down, i.e., leader of group containing b becomes the leader of the merged group. If a is in b's group or vice versa ignore the operation.
2 a: a becomes the leader of his group.
3 a: Output the leader of the group containing person a.
Output:
Output the answer for each query of type 3.
Constraints:
1 <= N <= 105
1 <= Q <= 105
SAMPLE INPUT
2 2
1 1 2
3 1
SAMPLE OUTPUT
2
Explanation
Here, 2 will take over after 1 steps down.
--------------------------------------------------------------EDITORIAL-------------------------------------------------------
JUST  CHANGE THE REPRESENTATIVE OF THE  GROUP ....
---------------------------------------------------------CODE--------------------------------------------------------------------
#include<bits/stdc++.h>
using namespace std;
typedef long long int lli;
lli parent[1000000];
lli rankk[1000000];
lli find(lli a)
  {
    if(parent[a]!=parent[parent[a]])
     {
      parent[a]=find(parent[a]);
     }
     return parent[a];
 }

 int merge(int a,int b)
  {
  int pa=find(a);
  int pb=(find(b));
  parent[pb]=pa;
  rankk[pb]=0;
  //parent[a]=a;
  }
int main()
{
int n;
 cin>>n;
 int q;
  cin>>q;
  for(int i=0;i<=n;i++)
  {
  rankk[i]=1;
  parent[i]=i;
  }
  for(int i=0;i<q;i++)
  {
  int type ;
  cin>>type;
  if(type==1)
  {
  int a,b;
   cin>>a>>b;
  if(find(a)!=find(b))
       {
         merge(b,a);
   
 }
}
else if(type==2)
{
int a;
cin>>a;
int pa=find(a);
parent[pa]=a;
rankk[pa]=0;
parent[a]=a;
}
else
{
int a;
cin>>a;
// cout<<"call "<<endl;
cout<<find(a)<<endl;
// cout<<"call "<<endl;
}

  }
  return 0;
}

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