Submission #399563

#	Time	Username	Problem	Language	Result	Execution time	Memory
399563		Osama_Alkhodairy	Inside information (BOI21_servers)	C++17	50 / 100	295 ms	41248 KiB

servers

#include <bits/stdc++.h>
using namespace std;
#define finish(x) return cout << x << endl, 0
#define ll long long

const int N = 120001;
const int K = 18;

struct query{
    char c;
    int x, y;
};

int n, k, w[N], dep[N], p[N][K], s[N][K], dsu[N];
vector <query> a;
vector <pair <int, int> > v[N];

int lift(int node, int k){
    for(int i = 0 ; i < K ; i++){
        if((k >> i) & 1){
            node = p[node][i];
        }
    }
    return node;
}
int LCA(int a, int b){
    if(dep[b] < dep[a]) swap(a, b);
    b = lift(b, dep[b] - dep[a]);
    if(a == b) return a;
    for(int i = K - 1 ; i >= 0 ; i--){
        if(p[a][i] != p[b][i]){
            a = p[a][i];
            b = p[b][i];
        }
    }
    return p[a][0];
}
int calc_s(int node, int k){
    int ret = 0;
    for(int i = 0 ; i < K ; i++){
        if((k >> i) & 1){
            ret += s[node][i];
            node = p[node][i];
        }
    }
    return ret;
}
void dfs(int node, int pnode){
    s[node][0] = w[node] < w[p[node][0]];
    for(int i = 1 ; i < K ; i++){
        p[node][i] = p[p[node][i - 1]][i - 1];
        s[node][i] = s[node][i - 1] + s[p[node][i - 1]][i - 1];
    }
    for(auto &i : v[node]){
        if(i.first == pnode) continue;
        w[i.first] = i.second;
        p[i.first][0] = node;
        dep[i.first] = dep[node] + 1;
        dfs(i.first, node);
    }
}
int find(int x){
    if(dsu[x] == x) return x;
    return dsu[x] = find(dsu[x]);
}
void merge(int x, int y){
    x = find(x);
    y = find(y);
    dsu[x] = y;
}
int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin >> n >> k;
    a.resize(n + k - 1);
    for(auto &i : a){
        cin >> i.c >> i.x;
        if(i.c == 'S' || i.c == 'Q'){
            cin >> i.y;
        }
    }
    int ed = 0;
    for(auto &i : a){
        if(i.c == 'S'){
            v[i.x].push_back(make_pair(i.y, ed));
            v[i.y].push_back(make_pair(i.x, ed));
            ed++;
        }
    }
    dfs(1, 0);
    for(int i = 1 ; i <= n ; i++){
        dsu[i] = i;
    }
    for(auto &i : a){
        if(i.c == 'S'){
            merge(i.x, i.y);
        }
        else if(i.c == 'Q'){
            if(find(i.x) != find(i.y)){
                cout << "no\n";
                continue;
            }
            int lca = LCA(i.x, i.y);
            bool ok = 1;
            if(i.x != lca && calc_s(i.x, dep[i.x] - dep[lca] - 1) > 0) ok = 0;
            if(i.y != lca && calc_s(i.y, dep[i.y] - dep[lca] - 1) != dep[i.y] - dep[lca] - 1) ok = 0;
            if(i.x != lca && i.y != lca && w[lift(i.x, dep[i.x] - dep[lca] - 1)] < w[lift(i.y, dep[i.y] - dep[lca] - 1)]) ok = 0;
            if(ok) cout << "yes\n";
            else 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