제출 #205162

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
205162		cheetose	Mergers (JOI19_mergers)	C++11	100 / 100	1625 ms	131348 KiB

mergers

#include <bits/stdc++.h>
#define mp make_pair
#define pb push_back
#define X first
#define Y second
#define y0 y12
#define y1 y22
#define INF 987654321987654321
#define PI 3.141592653589793238462643383279502884
#define fup(i,a,b,c) for(int (i)=(a);(i)<=(b);(i)+=(c))
#define fdn(i,a,b,c) for(int (i)=(a);(i)>=(b);(i)-=(c))
#define MEM0(a) memset((a),0,sizeof(a));
#define MEM_1(a) memset((a),-1,sizeof(a));
#define ALL(a) a.begin(),a.end()
#define SYNC ios_base::sync_with_stdio(false);cin.tie(0)
using namespace std;
typedef long long ll;
typedef long double ld;
typedef double db;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef pair<int, int> Pi;
typedef pair<ll, ll> Pll;
typedef pair<ld, ld> Pd;
typedef vector<int> Vi;
typedef vector<ll> Vll;
typedef vector<ld> Vd;
typedef vector<Pi> VPi;
typedef vector<Pll> VPll;
typedef vector<Pd> VPd;
typedef tuple<int, int, int> iii;
typedef tuple<int, int, int, int> iiii;
typedef tuple<ll, ll, ll> LLL;
typedef vector<iii> Viii;
typedef vector<LLL> VLLL;
typedef complex<double> base;
const int MOD = 42043;
ll POW(ll a, ll b, ll MMM = MOD) { ll ret = 1; for (; b; b >>= 1, a = (a*a) % MMM)if (b & 1)ret = (ret*a) % MMM; return ret; }
ll gcd(ll a, ll b) { return b ? gcd(b, a%b) : a; }
ll lcm(ll a, ll b) { if (a == 0 || b == 0)return a + b; return a*(b / gcd(a, b)); }
int dx[] = { 0,1,0,-1,1,1,-1,-1 }, dy[] = { 1,0,-1,0,1,-1,1,-1 };
int ddx[] = { -1,-2,1,-2,2,-1,2,1 }, ddy[] = { -2,-1,-2,1,-1,2,1,2 };

Vi v[500005],col[500005];
Pi d[2][500005];
bool chk[500005];
int a[500005];
ll sub[500005];
int cnt[500005],deg[500005];
int par[500005];
int find(int a)
{
	if (par[a] < 0)return a;
	return par[a] = find(par[a]);
}
void merge(int a, int b)
{
	a = find(a), b = find(b);
	if (a != b)par[b] = a;
}
int n,k;
int dfs(int N,int p=-1,bool ok=0)
{
	if(chk[N])ok=1;
	int tt=0;
	for(int next:v[N])
	{
		if(next==p)continue;
		if(cnt[next]>0)tt++;
	}
	if(tt>1)ok=1;
	for(int next:v[N])
	{
		if(next==p)continue;
		dfs(next,N,ok);
		if(ok && cnt[next]>0)deg[N]++,deg[next]++;
	}
}
int parent[500005][19], depth[500005];
void dfs2(int N,int p,int d)
{
	depth[N]=d;
	parent[N][0]=p;
	for(int next:v[N])
	{
		if(next==p)continue;
		dfs2(next,N,d+1);
	}
}
int LCA(int x, int y)
{
	if (depth[x] < depth[y])swap(x, y);
	int dif = depth[x] - depth[y];
	for (int j = 0; dif > 0; j++)
	{
		if (dif & 1)x = parent[x][j];
		dif >>= 1;
	}

	if (x != y)
	{
		fdn(j,18,0,1)
		{
			if (parent[x][j] != -1 && parent[x][j] != parent[y][j])
			{
				x = parent[x][j];
				y = parent[y][j];
			}
		}
		x = parent[x][0];
	}
	return x;
}
void dfs4(int N,int p=-1)
{
	cnt[N]=chk[N];
	for(int next:v[N])
	{
		if(next==p)continue;
		dfs4(next,N);
		cnt[N]+=cnt[next];
	}
}
int main() {
	MEM_1(par);MEM_1(parent);
	scanf("%d%d",&n,&k);
	fup(i,1,n-1,1)
	{
		int x,y;
		scanf("%d%d",&x,&y);
		v[x].pb(y);
		v[y].pb(x);
	}
	fup(i,1,n,1)
	{
		scanf("%d",a+i),a[i]--;
		col[a[i]].pb(i);
	}
	dfs2(1,-1,0);
	fup(j,0,17,1)
		fup(i,1,n,1)
		if (parent[i][j] != -1)
			parent[i][j + 1] = parent[parent[i][j]][j];
	fup(i,0,k-1,1)
	{
		if(col[i].size()<=1)continue;
		int now=col[i][0];
		fup(j,1,(int)col[i].size()-1,1)
		{
			int u=LCA(now,col[i][j]);
			while(find(u)!=find(col[i][j]))
			{
				col[i][j]=find(col[i][j]);
				merge(parent[col[i][j]][0],col[i][j]);
			}
			while(find(u)!=find(now))
			{
				now=find(now);
				merge(parent[now][0],now);
			}
			now=u;
		}
	}
	fup(i,1,n,1)
	{
		for(int x:v[i])
			if(find(i)!=find(x))chk[i]=chk[x]=1;
	}
	dfs4(1);
	dfs(1);
	int res=0;
	fup(i,1,n,1)if(deg[i]==1)res++;
	printf("%d\n",res+1>>1);
}

컴파일 시 표준 에러 (stderr) 메시지

mergers.cpp: In function 'int dfs(int, int, bool)':
mergers.cpp:78:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
mergers.cpp: In function 'int main()':
mergers.cpp:173:19: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  printf("%d\n",res+1>>1);
                ~~~^~
mergers.cpp:126:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&k);
  ~~~~~^~~~~~~~~~~~~~
mergers.cpp:130:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",&x,&y);
   ~~~~~^~~~~~~~~~~~~~
mergers.cpp:136:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",a+i),a[i]--;
   ~~~~~~~~~~~~~~~^~~~~~~

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