Submission #125464

#	Time	Username	Problem	Language	Result	Execution time	Memory
125464		ioilolcom	Pictionary (COCI18_pictionary)	C++14	140 / 140	178 ms	30484 KiB

pictionary

#include <bits/stdc++.h>
using namespace std;
#define endl "\n"
typedef long long int ll;
const int N=1e5+7;
vector<int> adj[N];
int p[N];
int P[30][N];
int ans[30][N];
int L[N];
int n,m,q;
int gcd(int a,int b){
	if(b==0) {
		return a;
	}
	return gcd(b,a%b);
}
void dfs(int u,int p){
	L[u]=L[p]+1;
	P[0][u]=p;
	ans[0][u]=gcd(u,p);
	for(int v:adj[u]) {
		if(v==p) continue;
		dfs(v,u);
	}
}


void do_stuff(){
	for(int i=1; i<28; i++) {
		for(int j=1; j<=n; j++) {
			P[i][j]=P[i-1][P[i-1][j]];
			ans[i][j]=min(ans[i-1][P[i-1][j]],ans[i-1][j]);
		}
	}
}
void init(){
	for(int i=1; i<=n; i++) {
		p[i]=i;
	}
}
int find(int x){
	return (p[x]==x) ? x : p[x]=find(p[x]);
}
bool merge(int a,int b){
	int u=find(a);
	int v=find(b);
	if(u==v) return 0;
	p[u]=v;
	return 1;
}
int lca(int a,int b){
	int mx=1e9;
	if(L[b]<L[a]) {
		swap(a,b);
	}

	int d=L[b]-L[a];

	for(int i=28; i>=0; i--) {
		if((1<<i)&d) {
			mx=min(mx,ans[i][b]);
			//cout<<i<<" "<<ans[i][b]<<endl;
			b=P[i][b];
		}
	}

	if(a==b) {
		return mx;
	}

	for(int i=28; i>=0; i--) {
		if(P[i][a]!=P[i][b]) {
			mx=min(mx,ans[i][a]);
			mx=min(mx,ans[i][b]);
			a=P[i][a];
			b=P[i][b];
		}
	}
	mx=min({mx,ans[0][a],ans[0][b]});
	return mx;
}
int main()
{

	ios_base:: sync_with_stdio(false); cin.tie(0); cout.tie(0);
	cin>>n>>m>>q;
	init();
	for(int i=m; i>=1; i--) {
		for(int j=i+i; j<=n; j+=i) {
			if(merge(i,j)) {
				adj[i].push_back(j);
				adj[j].push_back(i);
			}
		}
	}
	dfs(1,0);
	do_stuff();
	while(q--) {
		int a,b;
		cin>>a>>b;
		int ans=lca(a,b);
		assert(ans!=1e9);
		cout<<m-ans+1<<endl;
	}


	return 0;
}

• Subtask 1: 14 / 14
• Subtask 2: 14 / 14
• Subtask 3: 14 / 14
• Subtask 4: 14 / 14
• Subtask 5: 14 / 14
• Subtask 6: 14 / 14
• Subtask 7: 14 / 14
• Subtask 8: 14 / 14
• Subtask 9: 14 / 14
• Subtask 10: 14 / 14