Submission #595302

#	Time	Username	Problem	Language	Result	Execution time	Memory
595302		dxz05	Railway Trip 2 (JOI22_ho_t4)	C++14	25 / 100	344 ms	44956 KiB

Main

//#pragma GCC optimize("Ofast,O2,O3,unroll-loops")
//#pragma GCC target("avx2")

#include <bits/stdc++.h>

using namespace std;

void debug_out() { cerr << endl; }

template<typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
    cerr << "[" << H << "]";
    debug_out(T...);
}

#ifdef dddxxz
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif

#define SZ(s) ((int)s.size())
#define all(x) (x).begin(), (x).end()
#define lla(x) (x).rbegin(), (x).rend()
#define bpc(x) __builtin_popcount(x)
#define bpcll(x) __builtin_popcountll(x)
#define MP make_pair

clock_t startTime;

double getCurrentTime() {
    return (double) (clock() - startTime) / CLOCKS_PER_SEC;
}

mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());

typedef long long ll;
const int MOD = 1e9 + 7;
const int INF = 1000000101;
const long long LLINF = 1223372000000000555;
const int N = 1e5 + 3e2;
const int M = 5555;

int get_kth(int x, int k, const vector<vector<int>> &p){
    for (int i = 0; i < p[x].size(); i++){
        if (k & (1 << i)) x = p[x][i];
    }
    return x;
}

void solve(int TC) {
    int n, k, trips;
    cin >> n >> k >> trips;

    assert(k == n - 1);

    vector<vector<int>> open_l(n), close_l(n);
    vector<vector<int>> open_r(n), close_r(n);
    while (trips--){
        int a, b;
        cin >> a >> b;
        --a, --b;

        if (a < b){
            open_r[a].push_back(b);
            close_r[b - 1].push_back(b);
        } else {
            open_l[a].push_back(b);
            close_l[b + 1].push_back(b);
        }

    }

    vector<int> lf(n), rg(n);
    iota(all(lf), 0);
    iota(all(rg), 0);

    multiset<int> ms;
    for (int i = 0; i < n; i++){
        for (int r : open_r[i]) ms.insert(r);
        if (!ms.empty()) rg[i] = *ms.rbegin();
        for (int r : close_r[i]) ms.erase(ms.find(r));
    }

    ms.clear();
    for (int i = n - 1; i >= 0; i--){
        for (int l : open_l[i]) ms.insert(l);
        if (!ms.empty()) lf[i] = *ms.begin();
        for (int l : close_l[i]) ms.erase(ms.find(l));
    }

    vector<vector<int>> pl(n, vector<int>(20, 0));
    for (int i = 0; i < n; i++){
        pl[i][0] = lf[i];
        for (int j = 1; j < 20; j++){
            pl[i][j] = pl[pl[i][j - 1]][j - 1];
        }
    }

    vector<vector<int>> pr(n, vector<int>(20, 0));
    for (int i = n - 1; i >= 0; i--){
        pr[i][0] = rg[i];
        for (int j = 1; j < 20; j++){
            pr[i][j] = pr[pr[i][j - 1]][j - 1];
        }
    }

    int q;
    cin >> q;

    while (q--){
        int s, t;
        cin >> s >> t;
        --s, --t;

        if (s < t){
            int l = 0, r = n;
            while (l <= r){
                int m = (l + r) >> 1;
                if (get_kth(s, m, pr) >= t){
                    r = m - 1;
                } else {
                    l = m + 1;
                }
            }
            if (r == n) r = -2;
            cout << r + 1 << endl;
        } else {
            int l = 0, r = n;
            while (l <= r){
                int m = (l + r) >> 1;
                if (get_kth(s, m, pl) <= t){
                    r = m - 1;
                } else {
                    l = m + 1;
                }
            }
            if (r == n) r = -2;
            cout << r + 1 << endl;
        }

    }

}

int main() {
    startTime = clock();
    ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);

#ifdef dddxxz
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif

    int TC = 1;
//    cin >> TC;

    for (int test = 1; test <= TC; test++) {
        //debug(test);
        //cout << "Case #" << test << ": ";
        solve(test);
    }

#ifdef dddxxz
    cerr << endl << "Time: " << int(getCurrentTime() * 1000) << " ms" << endl;
#endif

    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int get_kth(int, int, const std::vector<std::vector<int> >&)':
Main.cpp:45:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   45 |     for (int i = 0; i < p[x].size(); i++){
      |                     ~~^~~~~~~~~~~~~

• Subtask 1: 0 / 8
• Subtask 2: 0 / 8
• Subtask 3: 0 / 11
• Subtask 4: 25 / 25
• Subtask 5: 0 / 35
• Subtask 6: 0 / 13