제출 #469118

#제출 시각아이디문제언어결과실행 시간메모리
469118flashmtAliens (IOI16_aliens)C++17
4 / 100
1 ms204 KiB
#include <bits/stdc++.h> using namespace std; const long long oo = 1LL << 60; using ll = long long; struct Line { mutable ll k, m, p; // y = kx + m bool operator<(const Line& o) const { return k < o.k; } bool operator<(ll x) const { return p < x; } }; struct LineContainer : multiset<Line, less<>> { // (for doubles, use inf = 1/.0, div(a,b) = a/b) const ll inf = LLONG_MAX; ll div(ll a, ll b) { // floored division return a / b - ((a ^ b) < 0 && a % b); } bool isect(iterator x, iterator y) { if (y == end()) { x->p = inf; return false; } if (x->k == y->k) x->p = x->m > y->m ? inf : -inf; else x->p = div(y->m - x->m, x->k - y->k); return x->p >= y->p; } void add(ll k, ll m) { auto z = insert({k, m, 0}), y = z++, x = y; while (isect(y, z)) z = erase(z); if (x != begin() && isect(--x, y)) isect(x, y = erase(y)); while ((y = x) != begin() && (--x)->p >= y->p) isect(x, erase(y)); } ll query(ll x) { assert(!empty()); auto l = *lower_bound(x); return l.k * x + l.m; } }; long long take_photos(int n, int m, int k, vector<int> r, vector<int> c) { vector<pair<int, int>> a = {{-1, -1}}; for (int i = 0; i < n; i++) a.push_back({min(r[i], c[i]), max(r[i], c[i]) + 1}); sort(begin(a), end(a)); int cur = 0; for (int i = 1; i <= n; i++) if (a[i].first == a[cur].first) a[cur].second = a[i].second; else if (a[i].second > a[cur].second) a[++cur] = a[i]; n = cur; auto sqr = [&](int x) { return 1LL * x * x; }; long long ans = oo; vector<long long> f(n + 1, oo); f[0] = 0; for (int i = 1; i <= k; i++) { LineContainer lc; vector<long long> newF(n + 1, oo); for (int j = 1; j <= n; j++) { long long value = f[j - 1] + sqr(a[j].first) - sqr(max(0, a[j - 1].second - a[j].first)); if (f[j - 1] != oo) lc.add(- a[j].first * 2, value); if (!lc.empty()) newF[j] = lc.query(a[j].second) + sqr(a[j].second); } swap(f, newF); ans = min(ans, f[n]); } return ans; }
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