Submission #711845

#	Time	Username	Problem	Language	Result	Execution time	Memory
711845		becaido	Event Hopping (BOI22_events)	C++17	100 / 100	176 ms	15816 KiB

events

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx,popcnt,sse4,abm")
#include <bits/stdc++.h>
using namespace std;

#ifdef WAIMAI
#define debug(HEHE...) cout << "[" << #HEHE << "] : ", dout(HEHE)
void dout() {cout << '\n';}
template<typename T, typename...U>
void dout(T t, U...u) {cout << t << (sizeof... (u) ? ", " : ""), dout (u...);}
#else
#define debug(...) 7122
#endif

#define ll long long
#define Waimai ios::sync_with_stdio(false), cin.tie(0)
#define FOR(x,a,b) for (int x = a, I = b; x <= I; x++)
#define pb emplace_back
#define F first
#define S second

#define lpos pos*2
#define rpos pos*2+1

const int SIZE = 1e5 + 5;
const int H = __lg(SIZE) + 1;

int n, q;
pair<int, int> a[SIZE], p[SIZE];
vector<int> lis;

pair<int, int> node[4 * SIZE];
int to[SIZE][H + 1];

void build(int pos, int l, int r) {
    if (l == r) {
        node[pos] = a[l];
        return;
    }
    int mid = (l + r) / 2;
    build(lpos, l, mid);
    build(rpos, mid + 1, r);
    node[pos] = min(node[lpos], node[rpos]);
}

pair<int, int> que(int pos, int l, int r, int L, int R) {
    if (l == L && r == R) return node[pos];
    int mid = (L + R) / 2;
    if (r <= mid) return que(lpos, l, r, L, mid);
    else if (l > mid) return que(rpos, l, r, mid + 1, R);
    return min(que(lpos, l, mid, L, mid), que(rpos, mid + 1, r, mid + 1, R));
}

void solve() {
    cin >> n >> q;
    FOR (i, 1, n) {
        auto &[l, r] = p[i];
        cin >> l >> r;
        lis.pb(r);
    }
    sort(lis.begin(), lis.end());
    lis.erase(unique(lis.begin(), lis.end()), lis.end());
    fill(a + 1, a + n + 1, make_pair(INT_MAX, 0));
    FOR (i, 1, n) {
        int pos = lower_bound(lis.begin(), lis.end(), p[i].S) - lis.begin() + 1;
        a[pos] = min(a[pos], {p[i].F, i});
    }
    build(1, 1, n);
    FOR (i, 1, n) {
        int l = lower_bound(lis.begin(), lis.end(), p[i].F) - lis.begin() + 1;
        int r = lower_bound(lis.begin(), lis.end(), p[i].S) - lis.begin() + 1;
        to[i][0] = que(1, l, r, 1, n).S;
        debug(i, to[i][0]);
    }
    FOR (j, 1, H) FOR (i, 1, n) to[i][j] = to[to[i][j - 1]][j - 1];
    while (q--) {
        int x, y, ans = 1;
        cin >> x >> y;
        if (x == y || (p[y].F <= p[x].S && p[x].S <= p[y].S)) {
            cout << (x != y) << '\n';
            continue;
        }
        for (int i = H; ~i; i--) if (p[x].S < p[to[y][i]].F) {
            ans += 1 << i;
            y = to[y][i];
            debug(ans, y);
        }
        y = to[y][0];
        debug(ans, y);
        if (p[x].S < p[y].F || p[x].S > p[y].S) cout << "impossible\n";
        else cout << ans + (p[x].S >= p[y].F) << '\n';
    }
}

int main() {
    Waimai;
    solve();
}

Compilation message (stderr)

events.cpp: In function 'void solve()':
events.cpp:12:20: warning: statement has no effect [-Wunused-value]
   12 | #define debug(...) 7122
      |                    ^~~~
events.cpp:73:9: note: in expansion of macro 'debug'
   73 |         debug(i, to[i][0]);
      |         ^~~~~
events.cpp:12:20: warning: statement has no effect [-Wunused-value]
   12 | #define debug(...) 7122
      |                    ^~~~
events.cpp:86:13: note: in expansion of macro 'debug'
   86 |             debug(ans, y);
      |             ^~~~~
events.cpp:12:20: warning: statement has no effect [-Wunused-value]
   12 | #define debug(...) 7122
      |                    ^~~~
events.cpp:89:9: note: in expansion of macro 'debug'
   89 |         debug(ans, y);
      |         ^~~~~

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