Submission #102728

#	Time	Username	Problem	Language	Result	Execution time	Memory
102728		psmao	Mergers (JOI19_mergers)	C++14	100 / 100	1187 ms	87288 KiB

mergers

#include <bits/stdc++.h>
using namespace std;

#define fo(i,s,t) for(int i = s; i <= t; ++ i)
#define fd(i,s,t) for(int i = s; i >= t; -- i)
#define bf(i,s) for(int i = head[s]; i; i = e[i].next)
#define mp make_pair
#define fi first
#define se second
#define pii pair<int,int>
#define pb push_back
#define VI vector<int>
#define sf scanf
#define pf printf
#define fp freopen
#define SZ(x) ((int)(x).size())
#ifdef MPS
#define D(x...) printf(x)
#else
#define D(x...)
#endif
typedef long long ll;
typedef double db;
typedef unsigned long long ull;
const int inf = 1<<30;
const ll INF = 1ll<<60;
const db Inf = 1e20;
const db eps = 1e-9;

void gmax(int &a,int b){a = (a > b ? a : b);}
void gmin(int &a,int b){a = (a < b ? a : b);}

const int maxn = 500050;

int n, K, fa[maxn], par[maxn], dep[maxn], deg[maxn];
VI adj[maxn], col[maxn];

int getfa(int x) {return fa[x] == x ? x : fa[x] = getfa(fa[x]);}
void merge(int u, int v) {u = getfa(u); v = getfa(v); fa[u] = v;}
void combine(int u, int v)
{
	while(u != v)
	{
		if(dep[u] > dep[v])
		{
			merge(u, par[u]);
			u = getfa(par[u]);
		}
		else
		{
			merge(v, par[v]);
			v = getfa(par[v]);
		}
	}
}
void dfs(int u, int f = 0)
{
	for(auto p : adj[u]) if(p != f)
	{
		par[p] = u;
		dep[p] = dep[u] + 1;
		dfs(p, u);
	}
}
int main()
{
	#ifdef MPS	
		fp("1.in","r",stdin);
		fp("1.out","w",stdout);
	#endif
	sf("%d%d",&n,&K);
	fo(i,2,n)
	{
		int u, v; sf("%d%d",&u,&v);
		adj[u].pb(v); adj[v].pb(u);
	}	
	fo(i,1,n) fa[i] = i;
	fo(i,1,n) {int x; sf("%d",&x); col[x].pb(i);}
	dfs(1);
	fo(i,1,K) fo(j,1,SZ(col[i])-1) combine(col[i][j], col[i][0]);
	fo(i,1,n) for(auto p : adj[i]) 
		if(getfa(i) != getfa(p) && dep[i] + 1 == dep[p]) 
		{
			++ deg[getfa(i)]; ++ deg[getfa(p)];
		}
	int leaves = 0;
	fo(i,1,n) if(getfa(i) == i && deg[i] == 1) ++ leaves;
	pf("%d\n",(int)ceil(leaves/2.0));
	return 0;
}

Compilation message (stderr)

mergers.cpp: In function 'int main()':
mergers.cpp:71:4: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  sf("%d%d",&n,&K);
    ^
mergers.cpp:74:15: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   int u, v; sf("%d%d",&u,&v);
               ^
mergers.cpp:78:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  fo(i,1,n) {int x; sf("%d",&x); col[x].pb(i);}
                      ^

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