Submission #64796

#	Time	Username	Problem	Language	Result	Execution time	Memory
64796		kjp4155	족보 (KOI18_family)	C++17	100 / 100	753 ms	98900 KiB

family

#include <stdio.h>
#include <algorithm>
#include <utility>
#include <vector>
using namespace std;

typedef pair<int,int> Pi;

/* Union Find data structure */
int pa[300500], cnt[300500]; 
int find(int x){
	if( pa[x] == x ) return x;
	return pa[x] = find(pa[x]);
}
void uni(int a, int b){
	a = find(a); b = find(b);
	if( a == b ) return;
	pa[a] = b;
	cnt[b] += cnt[a];
}

struct event{
	int t, len, level, node;
	// Smaller event first. Deeper event first. 
	bool operator < (event e){
		if( len != e.len ) return len < e.len;
		return level > e.level;
	}
};

int N[2],K;
vector<int> E[2][300500];
int root[2];
int sz[2][300500], leaf[2][300500], level[2][300500];
int timer = 0;
Pi dfs(int t, int x, int l){
	level[t][x] = l;

	if( 1 <= x && x <= K ){
		timer++;
		leaf[t][x] = x;
		sz[t][x] = 1;
		return {x,1};
	}
	
	for(auto e : E[t][x]){
		Pi res = dfs(t, e, l+1);
		leaf[t][x] = res.first;
		sz[t][x] += res.second; 
	}
	
	return {leaf[t][x], sz[t][x]};
}

int main(){
	scanf("%d%d%d",&N[0],&N[1],&K);

	for(int i=1;i<=K;i++){
		pa[i] = i; cnt[i] = 1;
	}

	for(int t=0;t<2;t++){
		for(int i=1;i<=N[t];i++){
			int x; scanf("%d",&x);
			if( x == 0 ) root[t] = i;
			else E[t][x].push_back(i);
		}
	}

	dfs( 0, root[0] , 0);
	timer = 0;
	dfs( 1, root[1] , 0);

	vector<event> events;

	for(int t=0;t<2;t++){
		for(int i=K+1;i<=N[t];i++){
			events.push_back({t, sz[t][i], level[t][i], i});
		}
	}

	sort(events.begin(), events.end());

	for(auto e : events){
		//printf("[%d,%d] %d %d \n",e.t, e.node, e.len, e.level);
		for(auto x : E[e.t][e.node]){
			uni(leaf[e.t][e.node], leaf[e.t][x]);
		}
		//printf("%d %d\n",cnt[find(leaf[e.t][e.node])], e.len);
		if( cnt[find(leaf[e.t][e.node])] != e.len ){
			printf("NO\n");
			return 0;
		}
	}

	printf("YES\n");
}

Compilation message (stderr)

family.cpp: In function 'int main()':
family.cpp:56:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%d",&N[0],&N[1],&K);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
family.cpp:64:16: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    int x; scanf("%d",&x);
           ~~~~~^~~~~~~~~

• Subtask 1: 17 / 17
• Subtask 2: 27 / 27
• Subtask 3: 15 / 15
• Subtask 4: 41 / 41