Submission #1051923

#TimeUsernameProblemLanguageResultExecution timeMemory
1051923otariusAlternating Current (BOI18_alternating)C++17
0 / 100
12 ms3160 KiB
#include <bits/stdc++.h> #include <bits/extc++.h> using namespace __gnu_pbds; using namespace std; // #pragma GCC optimize("Ofast") // #pragma GCC optimize ("unroll-loops") // #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native") #define ff first #define sc second #define pb push_back #define ll long long #define pll pair<ll, ll> #define pii pair<int, int> #define ull unsigned long long #define all(x) (x).begin(),(x).end() // #define int long long // #define int unsigned long long // #define ordered_set(T) tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update> // #define ordered_multiset(T) tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update> void open_file(string filename) { freopen((filename + ".in").c_str(), "r", stdin); freopen((filename + ".out").c_str(), "w", stdout); } // const ll mod = 1e9 + 7; // const ll mod = 998244353; const ll inf = 1e9; const ll biginf = 1e18; const int maxN = 1e5 + 25; void solve() { int n, m; cin >> n >> m; pii v[m]; for (int i = 0; i < m; i++) { cin >> v[i].ff >> v[i].sc; } sort(v, v + m); int x = 0, y = 0, ans[m]; for (int i = 0; i < m; i++) { if (x > y) { ans[i] = 1; y = max(y, v[i].sc); } else { ans[i] = 0; x = max(x, v[i].ff); } } int xx[n + 5] = {}, yy[n + 5] = {}; for (int i = 0; i < m; i++) { if (ans[i] == 0) { xx[v[i].ff]++; xx[v[i].sc + 1]--; } else { yy[v[i].ff]++; yy[v[i].sc + 1]--; } } for (int i = 1; i <= n; i++) { xx[i] += xx[i - 1]; yy[i] += yy[i - 1]; if (!xx[i] || !yy[i]) { cout << "impossible"; return; } } for (int i = 0; i < m; i++) cout << ans[i]; } int32_t main() { ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); int t = 1; // cin >> t; while (t--) { solve(); cout << '\n'; } return 0; }

Compilation message (stderr)

alternating.cpp: In function 'void open_file(std::string)':
alternating.cpp:26:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   26 |     freopen((filename + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
alternating.cpp:27:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |     freopen((filename + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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