Submission #710797

#	Time	Username	Problem	Language	Result	Execution time	Memory
710797		sysia	Inside information (BOI21_servers)	C++17	0 / 100	37 ms	5500 KiB

servers

//Sylwia Sapkowska
#include <bits/stdc++.h>
#pragma GCC optimize("O3", "unroll-loops")
using namespace std;

void __print(int x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ", "; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? ", " : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifdef LOCAL
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif

#define int long long
typedef pair<int, int> T;
const int oo = 1e18, oo2 = 1e9+7, K = 20;
const int mod = 998244353;

//czy sciezka od a do b uzywa krawedzi ≤t i jest rosnaca??
struct Q{
	int a, b, t, idx; 
	Q(){}
	Q(int _a, int _b, int _t, int _idx){
		a = _a, b = _b, t = _t, idx = _idx;
	}
};

//to be done
struct C{
	int v, t, idx;
	C(){}
	C(int _v, int _t, int _idx){
		v = _v, t = _t, idx = _idx;
	}
};

struct DSU{
	vector<int>rep, sz;

	DSU(int n){
		rep.resize(n);
		iota(rep.begin(), rep.end(), 0);
		sz.assign(n, 1);
	}

	int f(int a){return a == rep[a] ? a : rep[a] = f(rep[a]);}

	bool sameset(int a, int b){
		return f(a) == f(b);
	}

	bool u(int a, int b){
		a = f(a); b = f(b);
		if (a == b) return false;
		if (sz[a] < sz[b]) swap(a, b);
		sz[a] += sz[b];
		rep[b] = a;
		return true;
	}
};

void solve(){
    int n, q; cin >> n >> q;
    int m = 1, idx = 1;
    vector<Q>Qque;
	vector<C>Cque;
	vector<int>ans(q+1);
	vector<vector<T>>g(n+1);
	vector<T>edges = {{0, 0}};
    for (int i = 1; i<n+q; i++){
		char c; cin >> c;
		if (c == 'S'){
			int a, b; cin >> a >> b;
			g[a].emplace_back(b, m);
			g[b].emplace_back(a, m);
			edges.emplace_back(a, b);
			m++;
		} else if (c == 'Q'){
			int a, b; cin >> a >> b;
			Qque.emplace_back(a, b, m, idx++);
		} else {
			int a; cin >> a;
			Cque.emplace_back(a, m, idx++);
		}
	}
	DSU dsu(n+2);
	vector up(n+1, vector<int>(K));
	vector mn(n+1, vector<int>(K, oo));
	vector<int>depth(n+1);
	vector<int>cost(n+1);
	function<void(int, int, int)>dfs = [&](int v, int pa, int c){
		up[v][0] = pa;
		cost[v] = c;
		for (int i = 1; i<K; i++) {
			up[v][i] = up[up[v][i-1]][i-1];
			if (i > 1) mn[v][i] = min(mn[v][i-1], mn[up[v][i-1]][i-1]);
		}
		for (auto [x, id]: g[v]){
			if (x == pa) continue;
			depth[x] = depth[v]+1;
			mn[x][1] = id - c;
			dfs(x, v, id);
		}
	};
	dfs(1, 1, -oo);
	auto lca = [&](int a, int b){
		if (depth[a] > depth[b]) swap(a, b);
		for (int i = K-1; i>=0; i--){
			if (depth[b] - (1<<i) >= depth[a]){
				b = up[b][i];
			}
		}
		if (a == b) return a;
		for (int i = K-1; i>=0; i--){
			if (up[a][i] != up[b][i]){
				a = up[a][i];
				b = up[b][i];
			}
		}
		return up[a][0];
	};
	int ptr = 0;
	auto is_increasing = [&](int a, int b){
		//sciezka pionowa od a do b (b w poddrzewie a)
		if (depth[b] - depth[a] <= 1) return true;
		int jump = depth[b] - depth[a] - 2;
		int currmn = oo, v = b;
		for (int i = K-1; i>=1; i--){
			if (jump&(1<<i)){
				currmn = min(currmn, mn[v][i]);
				v = up[v][i];
			}
		}
		return (currmn > 0);
	};
	debug(edges);
	auto below_lca = [&](int a, int b){
		bool f = 0;
		if (depth[a] < depth[b]) {
			swap(a, b);
			f = 1;
		}
		for (int i = K-1; i>=0; i--){
			if (depth[a] - (1<<i) >= depth[b]){
				a = up[a][i];
			}
		}
		assert(a != b);
		for (int i = K-1; i>=0; i--){
			if (up[a][i] != up[b][i]){
				a = up[a][i];
				b = up[b][i];
			}
		}
		if (f) swap(a, b);
		return T{a, b};
	};
	for (auto [a, b, t, id]: Qque){
		
		while (ptr + 1 < t){
			ptr++;
			dsu.u(edges[ptr].first, edges[ptr].second);
		}
		if (!dsu.sameset(a, b)) {
			cout << "no\n";
			continue;
		}
		int l = lca(a, b);
		debug(a, b, l);
		if (l == b){
			//sciezka ma byc rosnaca
			if (is_increasing(b, a)) cout << "yes\n";
			else cout << "no\n";
			continue;
		} 
		if (l == a){
			//sciezka ma byc malejaca
			if (!is_increasing(a, b)) cout << "yes\n";
			else cout << "no\n";
			continue;
		}
		//rosnaca od a do l i malejaca od l do b
		T now = below_lca(a, b);
		if (is_increasing(l, a) && !is_increasing(l, b) && cost[now.first] < cost[now.second]) cout << "yes\n";
		else cout << "no\n";
	}
}

int32_t main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    solve();

    return 0;
}

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