Submission #1112598

#	Time	Username	Problem	Language	Result	Execution time	Memory
1112598		FucKanh	Regions (IOI09_regions)	C++14	100 / 100	5191 ms	66276 KiB

regions

#include<bits/stdc++.h>
#define ll long long
#define int ll
#define pii pair<int,int>

using namespace std;

const int maxn = 2e5 + 2;

int tin[maxn], tout[maxn],t,pos[maxn];
int control[maxn], num[maxn];
vector<int> re[maxn],a[maxn];
vector<int> small,big;

void dfs(int u) {
    tin[u] = ++t;
    for (int v : a[u]){
        dfs(v);
    }
    tout[u] = t;
}

int compare(const int &a, const int &b) {
    return tin[a] < tin[b];
}

void solve() {
    int n,r,q; cin >> n >> r >> q;
    int wat; cin >> wat;
    re[wat].push_back(1);
    int block = sqrt(n);
    for (int i = 2; i <= n; i++) {
        int x,y; cin >> x >> y;
        a[x].push_back(i);
        re[y].push_back(i);
    }
    dfs(1);

    for (int i = 1; i <= r; i++) {
        sort(re[i].begin(),re[i].end(),compare);
        if (re[i].size() > block) {
            big.push_back(i);
            pos[i] = big.size();
        }
        else {
            small.push_back(i);
            pos[i] = -small.size();
        }
    }

//    for (int i = 1; i <= r; i++) {
//        cerr << "region "<< i << " pos " << pos[i] << " : ";
//        for (int val : re[i]) cerr << val << " "; cerr << endl;
//    }

    vector<vector<int>> pre(big.size(), vector<int>(big.size(), 0));
    vector<vector<int>> stob(small.size(), vector<int>(big.size(), 0));
    vector<vector<int>> btos(big.size(), vector<int>(small.size(), 0));

    for (int i = 0; i < big.size(); i++) {
        memset(control,0,sizeof(control));
        memset(num,0,sizeof(num));
        for (int u : re[big[i]]) {
            num[tin[u]]++;
            control[tin[u]]++;
            control[tout[u]+1]--;
        }
        for (int v = 1; v <= n; v++) {
            num[v] += num[v-1];
            control[v] += control[v-1];
        }
        for (int j = i+1; j < big.size(); j++) {
            for (int u : re[big[j]]) {
                pre[i][j] += control[tin[u]];
                pre[j][i] += num[tout[u]] - num[tin[u]-1];
            }
        }
        for (int j = 0; j < small.size(); j++) {
            for (int u : re[small[j]]) {
                btos[i][j] += control[tin[u]];
                stob[j][i] += num[tout[u]] - num[tin[u]-1];
            }
        }
    }

    for (int i = 1; i <= q; i++) {
        int x,y; cin >> x >> y;
        if (pos[x] > 0 && pos[y] > 0) cout << pre[pos[x]-1][pos[y]-1] << endl;
        else if (pos[x] > 0 && pos[y] < 0) cout << btos[pos[x]-1][-pos[y]-1] << endl;
        else if (pos[x] < 0 && pos[y] > 0) cout << stob[-pos[x]-1][pos[y]-1] << endl;
        else {
            int l = 0;
            int ans = 0;
            stack<int> st;
//            vector<int> p = &re[-pos[y]-1];
            for (int u : re[y]) {
                while (st.size() && !(tin[st.top()] <= tin[u] && tout[st.top()] >= tout[u])) st.pop();
                while (l < re[x].size() && tin[re[x][l]] <= tin[u]) {
                    if (tin[re[x][l]] <= tin[u] && tout[re[x][l]] >= tout[u]) st.push(re[x][l]);
                    l++;
                }
//                if (i==2) cerr << u << " " << l << " " << st.size() << endl;
                ans += st.size();
            }
            cout << ans << endl;
        }
    }
}
void file(string name) {
    if (fopen((name + ".inp").c_str(), "r")) {
        freopen((name + ".inp").c_str(), "r", stdin);
        freopen((name + ".out").c_str(), "w", stdout);
    }
}
signed main() {
    file("REGIONS");
    cin.tie(0) -> sync_with_stdio(0);
    solve();
    return 0;
}

Compilation message (stderr)

regions.cpp: In function 'void solve()':
regions.cpp:41:26: warning: comparison of integer expressions of different signedness: 'std::vector<long long int>::size_type' {aka 'long unsigned int'} and 'long long int' [-Wsign-compare]
   41 |         if (re[i].size() > block) {
      |             ~~~~~~~~~~~~~^~~~~~~
regions.cpp:60:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   60 |     for (int i = 0; i < big.size(); i++) {
      |                     ~~^~~~~~~~~~~~
regions.cpp:72:29: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   72 |         for (int j = i+1; j < big.size(); j++) {
      |                           ~~^~~~~~~~~~~~
regions.cpp:78:27: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   78 |         for (int j = 0; j < small.size(); j++) {
      |                         ~~^~~~~~~~~~~~~~
regions.cpp:98:26: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   98 |                 while (l < re[x].size() && tin[re[x][l]] <= tin[u]) {
      |                        ~~^~~~~~~~~~~~~~
regions.cpp: In function 'void file(std::string)':
regions.cpp:111:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  111 |         freopen((name + ".inp").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
regions.cpp:112:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  112 |         freopen((name + ".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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