Submission #1192009

#TimeUsernameProblemLanguageResultExecution timeMemory
1192009shirokitoBuilding Bridges (CEOI17_building)C++20
100 / 100
55 ms66120 KiB
#include <bits/stdc++.h> using namespace std; using ll = long long; #define el '\n' const int N = 1e6 + 24; const ll INF = 4e18; int n; ll h[N], w[N]; ll pre[N], dp[N]; struct Line { ll a, b; ll calc(ll x) { return a * x + b; } }; struct Lichao { int n; vector<Line> t; Lichao(int sz) : t(4 * sz + 24, {0, LLONG_MAX}), n(sz) {} void update(int id, int l, int r, Line f) { if (l == r) { if (f.calc(l) < t[id].calc(l)) t[id] = f; return; } int mid = (l + r) >> 1; if (f.calc(mid) < t[id].calc(mid)) swap(f, t[id]); if (f.calc(l) < t[id].calc(l)) update(2 * id, l, mid, f); if (f.calc(r) < t[id].calc(r)) update(2 * id + 1, mid + 1, r, f); } ll get(int id, int l, int r, int i) { int mid = (l + r) >> 1; ll cur = t[id].calc(i); if (i == mid) return cur; else if (i < mid) return min(get(2 * id, l, mid, i), cur); else return min(get(2 * id + 1, mid + 1, r, i), cur); } }; void solve() { cin >> n; for (int i = 1; i <= n; i++) cin >> h[i]; for (int i = 1; i <= n; i++) cin >> w[i]; for (int i = 1; i <= n; i++) { pre[i] = pre[i - 1] + w[i]; } Lichao lct(N); dp[1] = 0; for (int i = 1; i <= n; i++) { if (i > 1) dp[i] = h[i] * h[i] + pre[i - 1] + lct.get(1, 0, N, h[i]); lct.update(1, 0, N, {-2 * h[i], dp[i] + h[i] * h[i] - pre[i]}); } cout << dp[n] << el; } int main() { cin.tie(NULL) -> sync_with_stdio(false); #define task "file" if (fopen(task".inp", "r")) { freopen(task".inp", "r", stdin); freopen(task".out", "w", stdout); } int T = 1; // cin >> T; while (T--) solve(); }

Compilation message (stderr)

building.cpp: In function 'int main()':
building.cpp:70:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   70 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
building.cpp:71:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   71 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
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