cpp_src/other/LineContainer.hpp

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• Last update: 2021-12-30 18:51:46+09:00
• Include: #include "cpp_src/other/LineContainer.hpp"
• Link: https://github.com/kth-competitive-programming/kactl/blob/master/content/data-structures/LineContainer.h

Verified with

• test/yukicoder/1297.test.cpp

Code

// modified
// https://github.com/kth-competitive-programming/kactl/blob/master/content/data-structures/LineContainer.h
// lines : y = kx + m
// find maximum at x

struct Line {
    mutable ll k, m, p;
    bool operator<(const Line& o) const { return k < o.k; }
    bool operator<(ll x) const { return p < x; }
};

template <bool maximum>
struct LineContainer : multiset<Line, less<>> {
    // (for doubles, use inf = 1/.0, div(a,b) = a/b)
    static const ll inf = numeric_limits<ll>::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()) return x->p = inf, 0;
        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) {
        if (!maximum) k = -k, m = -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);
        auto res = l.k * x + l.m;
        if (!maximum) res = -res;
        return res;
    }
};

#line 1 "cpp_src/other/LineContainer.hpp"
// modified
// https://github.com/kth-competitive-programming/kactl/blob/master/content/data-structures/LineContainer.h
// lines : y = kx + m
// find maximum at x

struct Line {
    mutable ll k, m, p;
    bool operator<(const Line& o) const { return k < o.k; }
    bool operator<(ll x) const { return p < x; }
};

template <bool maximum>
struct LineContainer : multiset<Line, less<>> {
    // (for doubles, use inf = 1/.0, div(a,b) = a/b)
    static const ll inf = numeric_limits<ll>::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()) return x->p = inf, 0;
        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) {
        if (!maximum) k = -k, m = -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);
        auto res = l.k * x + l.m;
        if (!maximum) res = -res;
        return res;
    }
};

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