제출 #721883

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
721883		drdilyor	Event Hopping (BOI22_events)	C++17	0 / 100	1545 ms	15508 KiB

events

#include<bits/stdc++.h>
using namespace std;
using ll = long long;
 
 
const int inf = 1e9 + 1e5;
struct event {
    int l, r, i;
};
 
int main() {
    int n, m;
    cin >> n >> m;
    vector<event> ev(n), og;
    map<int,int> comp;
    int _i = 0;
    for (auto& [s, e, i] : ev) {
        cin >> s >> e;
        comp[s] = comp[e] = 0;
        i = _i++;
    }
    int k = 0;
    for (auto& mp : comp)
        mp.second = k++;
    for (auto& [s, e, i] : ev)
        s = comp[s], e = comp[e];
 
    og = ev;
    sort(ev.begin(), ev.end(), [&](auto& a, auto& b) {
        return a.r == b.r ? a.l < b.l : a.r < b.r ;
    });
    //for (auto[a,b,c] : ev) cout << a << ' ' << b << ' ' << c <<'\n';
 
    vector jmp(20, vector(n, -1));
    for (int i = 0; i < n; i++) {
        int mxr = -1, mxi = -1;
        for (int j =0; j < n; j++) {
            if (ev[j].l <= ev[i].r && ev[i].r <= ev[j].r && ev[j].r > mxr) {
                mxr = ev[j].r;
                mxi = j;
            }
        }
        if (mxr != ev[i].r)
            jmp[0][i] = mxi;
    }
    for (int j = 1; j < 20; j++)
        for (int i = 0; i < n;i++)
            if (jmp[j-1][i] != -1)
                jmp[j][i] = jmp[j-1][jmp[j-1][i]];

    vector<int> iof(n);
    for (int i = 0; i < n; i++)
        iof[ev[i].i] = i;


    while (m--) {
        int s, e;
        cin >> s >> e;
        s--;e--;
 
        if (s == e) {
            cout << "0\n";
            continue;
        }
        if (og[e].l <= og[s].r && og[s].r <= og[e].r) {
            cout << "1\n";
            continue;
        }

        int si = iof[s], ei = iof[e];
 
        int res = 0;
        for (int j = 19; j >= 0; j--) {
            if (jmp[j][si] != -1 && ev[jmp[j][si]].r < ev[ei].l) {
                si = jmp[j][si];
                res += 1<<j;
            }
        }
        int j = jmp[0][si];
        if (j != -1 && jmp[0][j] != -1 && ev[ei].l <= ev[jmp[0][j]].r) {
            cout << res+2 << '\n';
        } else {
            cout << "impossible\n";
        }
    }
 
    return 0;
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 30