Submission #724399

#	Time	Username	Problem	Language	Result	Execution time	Memory
724399		Magikarp4000	Regions (IOI09_regions)	C++17	95 / 100	5387 ms	131072 KiB

regions

#include <bits/stdc++.h>
using namespace std;
#define OPTM ios_base::sync_with_stdio(0); cin.tie(0);
#define INF int(1e9+7)
#define ln '\n' 
#define ll long long
#define ull unsigned long long
#define ui unsigned int
#define us unsigned short
#define FOR(i,s,n) for (int i = s; i < n; i++)
#define FORR(i,n,s) for (int i = n; i > s; i--)
#define FORX(u, arr) for (auto u : arr)
#define PB push_back
#define in(v,x) (v.find(x) != v.end())
#define F first
#define S second
#define PII pair<int, int>
#define PLL pair<ll, ll>
#define UM unordered_map
#define US unordered_set
#define PQ priority_queue
#define ALL(v) v.begin(), v.end()
const ll LLINF = 1e18+1;

const int MAXN = 2e5+1, MAXR = 2.5e4+1;
int32_t n,r,q;
vector<int32_t> adj[MAXN];
vector<pair<int32_t,int32_t>> v[MAXR], reg[MAXR];
int32_t h[MAXN];
vector<int32_t> tour;
vector<int32_t> emp[MAXR];
int32_t mp[MAXN];
UM<int32_t,int32_t> pre[MAXR];
int timer;

void dfs(int s) {
    tour.PB(s);
    emp[h[s]].PB(s);
    v[h[s]].PB({timer,1});
    timer++;
    FORX(u,adj[s]) {
        dfs(u);
    }
    v[h[s]].PB({timer,-1});
}

int calc(int a, int b) {
    int i = 0, j = 0, res = 0;
    while (i < reg[a].size() && j < emp[b].size()) {
        if (reg[a][i].F < mp[emp[b][j]]) i++;
        else {
            res += reg[a][i].S;
            j++;
        }
    }
    return res;
}

signed main() {
    OPTM;
    cin >> n >> r >> q >> h[1];
    int blk = sqrt(n+.0)+1;
    FOR(i,2,n+1) {
        int x;
        cin >> x >> h[i];
        adj[x].PB(i);
    }
    dfs(1);
    FOR(i,0,n) mp[tour[i]] = i;
    FOR(i,1,r+1) {
        sort(ALL(v[i]));
        int vn = v[i].size();
        int j = 0, j1 = 0, cur = 0;
        while (j < vn) {
            if (v[i][j].F-1 >= 0) reg[i].PB({v[i][j].F-1,cur});
            cur += v[i][j].S;
            while (j+1 < vn && v[i][j+1].F == v[i][j].F) cur += v[i][++j].S;
            j++;
        }
        reg[i].PB({n-1,cur});
    }
    FOR(i,1,r+1) {
        if (emp[i].size() >= blk) {
            FOR(j,1,r+1) {
                if (i == j) continue;
                pre[i][j] = calc(i,j);
                pre[j][i] = calc(j,i);
            }
        }
    }
    FOR(_,0,q) {
        int a,b; cin >> a >> b;
        if (emp[a].size() >= blk || emp[b].size() >= blk) cout << pre[a][b];
        else cout << calc(a,b);
        cout << endl;
    }
}

Compilation message (stderr)

regions.cpp: In function 'int calc(int, int)':
regions.cpp:49:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   49 |     while (i < reg[a].size() && j < emp[b].size()) {
      |            ~~^~~~~~~~~~~~~~~
regions.cpp:49:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   49 |     while (i < reg[a].size() && j < emp[b].size()) {
      |                                 ~~^~~~~~~~~~~~~~~
regions.cpp: In function 'int main()':
regions.cpp:73:20: warning: unused variable 'j1' [-Wunused-variable]
   73 |         int j = 0, j1 = 0, cur = 0;
      |                    ^~
regions.cpp:83:27: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   83 |         if (emp[i].size() >= blk) {
      |             ~~~~~~~~~~~~~~^~~~~~
regions.cpp:93:27: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   93 |         if (emp[a].size() >= blk || emp[b].size() >= blk) cout << pre[a][b];
      |             ~~~~~~~~~~~~~~^~~~~~
regions.cpp:93:51: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   93 |         if (emp[a].size() >= blk || emp[b].size() >= blk) cout << pre[a][b];
      |                                     ~~~~~~~~~~~~~~^~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 80 / 85