Submission #1112750

#	Time	Username	Problem	Language	Result	Execution time	Memory
1112750		cpptowin	Event Hopping (BOI22_events)	C++17	100 / 100	215 ms	137616 KiB

events

#include <bits/stdc++.h>
#define fo(i, d, c) for (int i = d; i <= c; i++)
#define fod(i, c, d) for (int i = c; i >= d; i--)
#define maxn 1000010
#define N 1010
#define fi first
#define se second
#define pb emplace_back
#define en cout << "\n";
#define int long long
#define inf (int)1e18
#define bitcount(x) __builtin_popcountll(x)
#define pii pair<int, int>
#define vii vector<pii>
#define lb(x) x & -x
#define bit(i, j) ((i >> j) & 1)
#define offbit(i, j) (i ^ (1LL << j))
#define onbit(i, j) (i | (1LL << j))
#define vi vector<int>
#define all(x) x.begin(), x.end()
#define ss(x) (int)x.size()
#define UNIQUE(v) v.erase(unique(all(v)),v.end())
template <typename T1, typename T2>
bool minimize(T1 &a, T2 b)
{
    if (a > b)
    {
        a = b;
        return true;
    }
    return false;
}
template <typename T1, typename T2>
bool maximize(T1 &a, T2 b)
{
    if (a < b)
    {
        a = b;
        return true;
    }
    return false;
}
using namespace std;
const int nsqrt = 450;
const int mod = 1e9 + 7;
void add(int &x, int k)
{
    x += k;
    x %= mod;
    if(x < 0) x += mod;
}
void del(int &x, int k)
{
    x -= k;
    x %= mod;
    if(x < 0) x += mod;
}
int n,q;
array<int,3> a[maxn];
pii rmq[maxn][20];
pii minn[maxn][20];
vi nen;
pii getmin(int l,int r) 
{
    int lg = __lg(r - l + 1);
    return min(minn[l][lg],minn[r - (1 << lg) + 1][lg]);
}
main()
{
#define name "TASK"
    if (fopen(name ".inp", "r"))
    {
        freopen(name ".inp", "r", stdin);
        freopen(name ".out", "w", stdout);
    }
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cin >> n >> q;
    fo(i,1,n) 
    {
        cin >> a[i][0] >> a[i][1];
        nen.pb(a[i][0]);
        nen.pb(a[i][1]);
        a[i][2] = i;
    }
    sort(all(nen));UNIQUE(nen);
    fo(i,1,ss(nen)) fo(j,0,19) minn[i][j] = rmq[i][j] = {inf,inf};
    fo(i,1,n) 
    {
        a[i][0] = lower_bound(all(nen),a[i][0]) - nen.begin() + 1;
        a[i][1] = lower_bound(all(nen),a[i][1]) - nen.begin() + 1;
        minimize(minn[a[i][1]][0],make_pair(a[i][0],i));
    }
    fo(j,1,19) fo(i,1,ss(nen)) 
        minn[i][j] = min(minn[i][j - 1],minn[i + (1 << j - 1)][j - 1]);
    fo(i,1,n) 
    {
        rmq[i][0] = getmin(a[i][0],a[i][1]);
    }
    // cout << rmq[8][0].fi << ' ' << rmq[8][0].se;en;
    fo(j,1,19) fo(i,1,n) 
    {
        if(rmq[i][j - 1].fi == inf) continue;
        rmq[i][j] = rmq[rmq[i][j - 1].se][j - 1];
    }
    while(q--) 
    {
        int l,r;
        cin >> l >> r;
        if(a[r][1] < a[l][1]) 
        {
            cout << "impossible";en;
            continue;
        }
        if(l == r) 
        {
            cout << 0;en;
            continue;
        }
        if(a[r][0] <= a[l][1] and a[l][1] <= a[r][1])
        {
            cout << 1;en;
            continue;
        }
        int ans = 0;
        fod(i,19,0) if(rmq[r][i].fi != inf and rmq[r][i].fi > a[l][1]) 
        {
            ans += (1 << i);
            r = rmq[r][i].se;
            if(r == inf) break;
        }
        // cout << r;en;
        if(r != inf) 
        {
            r = rmq[r][0].se;
            ans++;
            if(r != inf and a[r][0] <= a[l][1] and a[r][1] >= a[l][1]) 
            {
                cout << ans + 1;en;
                continue;
            }
            else cout << "impossible \n";
        }
        else cout << "impossible\n";
    }
}

Compilation message (stderr)

events.cpp:68:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   68 | main()
      | ^~~~
events.cpp: In function 'int main()':
events.cpp:95:58: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
   95 |         minn[i][j] = min(minn[i][j - 1],minn[i + (1 << j - 1)][j - 1]);
      |                                                        ~~^~~
events.cpp:73:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   73 |         freopen(name ".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
events.cpp:74:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   74 |         freopen(name ".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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