Submission #1027026

#	Time	Username	Problem	Language	Result	Execution time	Memory
1027026		YassineBenYounes	Regions (IOI09_regions)	C++17	80 / 100	8034 ms	131072 KiB

regions

#include<bits/stdc++.h>
 
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef double db;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define pbds tree<int, null_type, less<int>,rb_tree_tag, tree_order_statistics_node_update>
using namespace __gnu_pbds;
ll gcd(ll a , ll b) {return b ? gcd(b , a % b) : a ;} // greatest common divisor (PGCD)
ll lcm(ll a , ll b) {return (a * b) / gcd(a , b);} // least common multiple (PPCM)
int dx[8] = {1, 0, 0, -1, 1, 1, -1, -1};
int dy[8] = {0, 1, -1, 0, 1, -1, -1, 1};
#define endl "\n"
#define ss second
#define ff first
#define all(x) (x).begin() , (x).end()
#define pb push_back
#define vi vector<int>
#define vii vector<pair<int,int>>
#define vl vector<ll>
#define vll vector<pair<ll,ll>>
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pdd  pair<double,double>
#define vdd  vector<pdd>
#define speed ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
using namespace std;
////////////////////Only Clear Code//////////////////////////
 
void usaco_problem(){
    freopen("milkvisits.in", "r", stdin);
    freopen("milkvisits.out", "w", stdout);
}
 
void init(){
    #ifndef ONLINE_JUDGE
 
freopen("input.txt", "r", stdin);
 
freopen("output.txt", "w", stdout);
 
#endif // ONLINE_JUDGE
}
const int mx = 2e5+5;
const int LOG = 22;
const int inf = 1e9;
const ll mod = 998244353;
const int sq = 320;
int arr[mx];

vi graph[mx];

int tin[mx], tout[mx];

int c = 0;

void dfs(int node, int p){
    tin[node] = c++;
    for(int adj : graph[node]){
        if(adj == p)continue;
        dfs(adj, node);
    }
    tout[node] = c++;
}

vi vect[mx];
vi nodes[mx];
int32_t main(){
    int n, r, q;cin >> n >> r >> q;
    for(int i = 1; i <= n;i++){
        if(i > 1){
            int a;cin >> a;
            graph[a].pb(i);
        }
        cin >> arr[i];
    }
    dfs(1, 1);
    for(int i = 1; i <= n;i++){
        vect[arr[i]].pb(tin[i]);
        nodes[arr[i]].pb(i);
    }
    for(int i = 1; i <= r;i++){
        sort(all(vect[i]));
    }
    map<pii, int > pre;
    for(int i = 1; i <= r;i++){
        if(vect[i].size() >= sq){
            for(int b = 1; b <= r;b++){
                int ans = 0;
                for(int x : nodes[i]){
                    int l = lower_bound(all(vect[b]), tin[x]) - vect[b].begin();
                    int r = lower_bound(all(vect[b]), tout[x]) - vect[b].begin();
                    ans += r-l;
                }
                pre[{i, b}] = ans;
            }
        }
    }
    while(q--){
        int a, b;cin >> a >> b;
        int ans = 0;
        if(pre.find({a, b}) != pre.end()){
            cout << pre[{a, b}] << endl;
            continue;
        }
        /*cout << a << " " << b << endl;
        for(int x : vect[b]){
            cout << x << " ";
        }
        cout << endl;*/

        for(int i : nodes[a]){
            int l = lower_bound(all(vect[b]), tin[i]) - vect[b].begin();
            int r = lower_bound(all(vect[b]), tout[i]) - vect[b].begin();
            ans += r-l;
        }
        cout << ans << endl;
        cout.flush();
    }
}
 
/*
    NEVER GIVE UP!
    DOING SMTHNG IS BETTER THAN DOING NTHNG!!!
    Your Guide when stuck:
    - Continue keyword only after reading the whole input
    - Don't use memset with testcases
    - Check for corner cases(n=1, n=0)
    - Check where you declare n(Be careful of declaring it globally and in main)
*/

Compilation message (stderr)

regions.cpp: In function 'void usaco_problem()':
regions.cpp:33:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |     freopen("milkvisits.in", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
regions.cpp:34:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   34 |     freopen("milkvisits.out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
regions.cpp: In function 'void init()':
regions.cpp:40:8: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   40 | freopen("input.txt", "r", stdin);
      | ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
regions.cpp:42:8: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   42 | freopen("output.txt", "w", stdout);
      | ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 65 / 85