Submission #1261840

#TimeUsernameProblemLanguageResultExecution timeMemory
1261840CrabCNHFire (BOI24_fire)C++20
40 / 100
133 ms37920 KiB
#include <bits/stdc++.h> #define task "BriantheCrab" #define int long long #define pii pair <int, int> #define fi first #define se second #define szf sizeof #define sz(s) (int)((s).size()) #define all(v) (v).begin(), (v).end() typedef long long ll; typedef unsigned long long ull; typedef long double ld; using namespace std; template <class T> void minimize (T &t, T f) {if (t > f) t = f;} template <class T> void maximize (T &t, T f) {if (t < f) t = f;} const int maxN = 2e5 + 5; const int inf = 1e18 + 7; const int mod = 1e9 + 7; const int LOG = 20; // khong tu code thi khong kha len duoc dau // biet sol roi thi tu lam not di int n, m; pii a[maxN]; int nxt[maxN][LOG]; void solve () { cin >> n >> m; vector <int> zip; for (int i = 1; i <= n; i ++) { int l, r; cin >> l >> r; a[i] = {l, r}; zip.push_back (l); zip.push_back (r); } sort (all (zip)); zip.erase (unique (all (zip)), zip.end ()); for (int i = 1; i <= n; i ++) { a[i].fi = lower_bound (all (zip), a[i].fi) - zip.begin () + 1; a[i].se = lower_bound (all (zip), a[i].se) - zip.begin () + 1; } m = sz (zip) + 1; for (int i = 1; i <= n; i ++) { if (a[i].fi < a[i].se) { maximize (nxt[a[i].fi][0], a[i].se); } } for (int i = 1; i <= m; i ++) { maximize (nxt[i][0], nxt[i - 1][0]); } for (int j = 1; j < LOG; j ++) { for (int i = 1; i <= m; i ++) { maximize (nxt[i][j], nxt[nxt[i][j - 1]][j - 1]); } for (int i = 1; i <= m; i ++) { maximize (nxt[i][j], nxt[i - 1][j]); } } //cout << nxt[4][0] << '\n'; int res = inf; for (int i = 1; i <= n; i ++) { if (a[i].fi < a[i].se) { continue; } int cost = 1; int st = a[i].se, en = a[i].fi; for (int j = LOG - 1; j >= 0; j --) { if (nxt[st][j] > 0 && nxt[st][j] < en) { cost += (1 << j); //cout << nxt[st][j] << ' ' << st << ' ' << j << '\n'; st = nxt[st][j]; } } if (nxt[st][0] >= en) { minimize (res, cost + 1); } } cout << (res > n ? -1 : res); return; } signed main () { cin.tie (nullptr) -> sync_with_stdio (false); if (fopen (task".inp", "r")) { freopen (task".inp", "r", stdin); freopen (task".out", "w", stdout); } int t = 1; //cin >> t; while (t --) { solve (); } return 0; } // thfvz

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:92:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   92 |         freopen (task".inp", "r", stdin);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:93:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   93 |         freopen (task".out", "w", stdout);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
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