Submission #575985

#	Time	Username	Problem	Language	Result	Execution time	Memory
575985		jiahng	Inside information (BOI21_servers)	C++14	50 / 100	342 ms	110156 KiB

servers

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

typedef long long ll;
//~ #define ll int
#define int ll
typedef pair<int32_t, int32_t> pi;
typedef vector <int> vi;
typedef vector <pi> vpi;
typedef pair<pi, ll> pii;
typedef set <ll> si;
typedef long double ld;
#define f first
#define s second
#define mp make_pair
#define FOR(i,s,e) for(int i=s;i<=int(e);++i)
#define DEC(i,s,e) for(int i=s;i>=int(e);--i)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define lbd(x, y) lower_bound(all(x), y)
#define ubd(x, y) upper_bound(all(x), y)
#define aFOR(i,x) for (auto i: x)
#define mem(x,i) memset(x,i,sizeof x)
#define fast ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0)
#define maxn 120001
#define INF 1e9
#define MOD 1000000007
typedef pair <vi, int> pvi;
typedef pair <int,pi> ipi;
typedef vector <pii> vpii;

int N,K;
vpi adj[maxn];
int sz[maxn], lvl[maxn],par[maxn][30];
void find_sz(int x, int p){
	sz[x] = 1;
	aFOR(i,adj[x]) if (i.f != p && lvl[i.f] == -1){
		find_sz(i.f,x); sz[x] += sz[i.f];
	}
}
int find_cent(int x,int p, int m){
	aFOR(i,adj[x]) if (i.f != p && lvl[i.f] == -1 && sz[i.f] > m / 2) return find_cent(i.f,x,m);
	return x;
}

bool inc[maxn][30], _dec[maxn][30];
int fi[maxn][30], la[maxn][30]; // All are measured top-down
void find_vals(int x, int p, int d, int incv, int decv, int first_edge, int last_edge){
	inc[x][d] = (incv != -1);
	_dec[x][d] = (decv != -1);
	fi[x][d] = first_edge;
	la[x][d] = last_edge;
	aFOR(i,adj[x]) if (i.f != p && lvl[i.f] == -1){
		int nincv, ndecv, nfirst_edge;
		if (incv == -1 || i.s < incv) nincv = -1;
		else nincv = i.s;
		
		if (decv == -1 || i.s > decv) ndecv = -1;
		else ndecv = i.s;
		
		if (first_edge == -1) nfirst_edge = i.s;
		else nfirst_edge = first_edge;
		
		find_vals(i.f, x, d, nincv, ndecv, nfirst_edge, i.s); 
	}
}
void decomp(int x,int p,int d){
	find_sz(x, -1);
	int cent = find_cent(x, -1, sz[x]);
	lvl[cent] = d;
	//~ cout << p << ' ' << cent << '\n';
	par[cent][d] = cent;
	FOR(i,0,d-1) par[cent][i] = par[p][i];
	
	find_vals(cent, -1, d, 0, N+1, -1, -1);
	
	aFOR(i,adj[cent]) if (lvl[i.f] == -1) decomp(i.f,cent, d+1);
}

char ch;
int a,b;
int32_t main(){
    fast;
    cin >> N >> K;
    int co = 1;
    
    vector <pii> queries;
    
    FOR(i,1,N+K-1){
		cin >> ch;
		
		if (ch == 'S'){
			cin >> a >> b;
			adj[a].pb(pi(b, co)); adj[b].pb(pi(a,co));
			co++;
		}else if (ch == 'Q'){
			cin >> a >> b;
			queries.pb(pii(pi(a,b), co-1));
		}else{
			cin >> a;
			queries.pb(pii(pi(a, -1), co-1));
		}
	}
	mem(lvl, -1);
	mem(par, -1);
	decomp(1,-1,0);

	aFOR(i,queries){
		if (i.f.s != -1){
			int x = i.f.s, y = i.f.f;
			if (x == y){
				cout << "yes\n"; continue;
			}
			int lca = 0;
			DEC(d,29,0) if (par[x][d] != -1 && par[x][d] == par[y][d]){
				lca = d;
				break;
			}
			//~ cout << lca << ' ';
			if (_dec[x][lca] && inc[y][lca]){
				if (fi[x][lca] == -1 || fi[y][lca] == -1 || 
					fi[x][lca] < fi[y][lca]){
					
					int last = la[y][lca];;
					if (lvl[y] == lca) last = fi[x][lca];
					if (last <= i.s){
						cout << "yes\n"; continue;
					}
				}
			}
			cout << "no\n";
			
		}
	}
}

• Subtask 1: 2.5 / 2.5
• Subtask 2: 0 / 2.5
• Subtask 3: 2.5 / 2.5
• Subtask 4: 0 / 2.5
• Subtask 5: 5 / 5
• Subtask 6: 0 / 5
• Subtask 7: 10 / 10
• Subtask 8: 0 / 10
• Subtask 9: 12.5 / 12.5
• Subtask 10: 0 / 12.5
• Subtask 11: 17.5 / 17.5
• Subtask 12: 0 / 17.5