Submission #211000

#	Time	Username	Problem	Language	Result	Execution time	Memory
211000		KoalaMuch	Mergers (JOI19_mergers)	C++14	0 / 100	125 ms	33368 KiB

mergers

#include<bits/stdc++.h>
using namespace std;
const int N = 5e5+5;
int p[N];
int belong[N];
int sz[N];
vector< int > g[N];
vector< int > state[N];
int fin(int i)  {return p[i]==i ? i : p[i]=fin(p[i]);}
int main()
{
    int n,k,u,v;
    scanf("%d %d",&n,&k);
    for(int i=1;i<n;i++)    scanf("%d %d",&u,&v),g[u].push_back(v),g[v].push_back(u);
    for(int i=1;i<=n;i++)   scanf("%d",&belong[i]),p[i] = i,sz[i] = 1;
    for(int i=1;i<=n;i++)
    {
        state[belong[i]].push_back(i);
        for(auto &x:g[i])
        {
            u = fin(i),v = fin(x);
            if(belong[u]==belong[v]&&u!=v)  sz[u]+=sz[v],p[v] = u;
        }
    }
    int ans = 0;
    for(int i=1;i<=k;i++)
    {
        if(state[i].size()==sz[fin(state[i][0])])
        {
            int cnt = 0;
            for(auto &x:state[i])
            {
                for(auto &y:g[x])
                {
                    cnt+=belong[y]!=i;
                }
            }
            if(cnt==1)  ++ans;
        }
    }
    printf("%d\n",ans >> 1);
    return 0;
}
/*
6 5
1 2 1 3 1 4 1 5 1 6
1 2 3 4 5 1
*/

Compilation message (stderr)

mergers.cpp: In function 'int main()':
mergers.cpp:28:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         if(state[i].size()==sz[fin(state[i][0])])
            ~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
mergers.cpp:13:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d",&n,&k);
     ~~~~~^~~~~~~~~~~~~~~
mergers.cpp:14:67: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for(int i=1;i<n;i++)    scanf("%d %d",&u,&v),g[u].push_back(v),g[v].push_back(u);
                             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
mergers.cpp:15:60: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for(int i=1;i<=n;i++)   scanf("%d",&belong[i]),p[i] = i,sz[i] = 1;
                             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 24
• Subtask 3: 0 / 14
• Subtask 4: 0 / 22
• Subtask 5: 0 / 30