Submission #995488

#	Time	Username	Problem	Language	Result	Execution time	Memory
995488		Forested	Meetings (IOI18_meetings)	C++17	17 / 100	68 ms	10460 KiB

meetings

#include <bits/stdc++.h>
using namespace std;
using i32 = int;
using i64 = long long;
template <typename T>
using V = vector<T>;
template <typename T>
using VV = V<V<T>>;
#define OVERRIDE4(a, b, c, d, ...) d
#define REP2(i, n) for (i32 i = 0; i < (i32)(n); ++i)
#define REP3(i, l, r) for (i32 i = (i32)(l); i < (i32)(r); ++i)
#define PER2(i, n) for (i32 i = (i32)(n) - 1; i >= 0; --i)
#define PER3(i, l, r) for (i32 i = (i32)(r) - 1; i >= (i32)(l); --i)
#define REP(...) OVERRIDE4(__VA_ARGS__, REP3, REP2)(__VA_ARGS__)
#define PER(...) OVERRIDE4(__VA_ARGS__, PER3, PER2)(__VA_ARGS__)
#define LEN(x) (i32)size(x)
#define ALL(x) begin(x), end(x)
template <typename T>
bool chmin(T &x, const T &y) {
    if (x > y) {
        x = y;
        return true;
    }
    return false;
}
template <typename T>
bool chmax(T &x, const T &y) {
    if (x < y) {
        x = y;
        return true;
    }
    return false;
}

#include "meetings.h"

constexpr i32 INF = 1001001001;
constexpr i64 INF64 = 3003003003003003003;

i64 solve_naive(V<i32> h) {
    i32 n = LEN(h);
    V<i64> cost(n, 0);
    V<pair<i64, i32>> stc;
    stc.emplace_back(INF, -1);
    i64 cur = 0;
    REP(i, n) {
        while (stc.back().first <= h[i]) {
            i64 v;
            i32 j;
            tie(v, j) = stc.back();
            stc.pop_back();
            cur -= v * (j - stc.back().second);
        }
        cur += (i64)h[i] * (i - stc.back().second);
        stc.emplace_back(h[i], i);
        cost[i] += cur;
    }
    stc.clear();
    stc.emplace_back(INF, n);
    cur = 0;
    PER(i, n) {
        while (stc.back().first <= h[i]) {
            i64 v;
            i32 j;
            tie(v, j) = stc.back();
            stc.pop_back();
            cur -= v * (stc.back().second - j);
        }
        cur += (i64)h[i] * (stc.back().second - i);
        stc.emplace_back(h[i], i);
        cost[i] += cur;
    }
    REP(i, n) {
        cost[i] -= h[i];
    }
    i64 mn = INF64;
    REP(i, n) {
        chmin(mn, cost[i]);
    }
    return mn;
}

struct Data {
    i32 len, l1, r1, m1;
};

Data id() {
    return Data{0, 0, 0, 0};
}

Data op(Data x, Data y) {
    i32 len = x.len + y.len;
    i32 l1 = (x.len == x.l1 ? x.len + y.l1 : x.l1);
    i32 r1 = (y.len == y.r1 ? x.r1 + y.len : y.r1);
    i32 m1 = max({x.m1, y.m1, x.r1 + y.l1});
    return Data{len, l1, r1, m1};
}

i32 ceil_pow2(i32 n) {
    i32 k = 1;
    while (k < n) {
        k *= 2;
    }
    return k;
}

class Segtree {
    i32 n;
    V<Data> dat;
    
public:
    Segtree(i32 _n) : n(ceil_pow2(_n)), dat(2 * n, id()) {}
    
    void update(i32 idx, Data d) {
        idx += n;
        dat[idx] = d;
        idx /= 2;
        while (idx > 0) {
            dat[idx] = op(dat[2 * idx], dat[2 * idx + 1]);
            idx /= 2;
        }
    }
    
    Data prod(i32 l, i32 r) const {
        l += n;
        r += n;
        Data lp = id(), rp = id();
        while (l < r) {
            if (l & 1) {
                lp = op(lp, dat[l++]);
            }
            if (r & 1) {
                rp = op(dat[--r], rp);
            }
            l /= 2;
            r /= 2;
        }
        return op(lp, rp);
    }
};

V<i64> minimum_costs(V<i32> _h, V<i32> l, V<i32> r) {
    i32 n = LEN(_h);
    i32 q = LEN(l);
    V<i64> h(n);
    REP(i, n) {
        h[i] = _h[i];
    }
    REP(i, q) {
        ++r[i];
    }
    
    REP(i, n) {
        assert(h[i] <= 2);
    }
    Segtree seg(n);
    REP(i, n) {
        seg.update(i, h[i] == 1 ? Data{1, 1, 1, 1} : Data{1, 0, 0, 0});
    }
    V<i64> ret(q);
    REP(i, q) {
        ret[i] = 2 * (r[i] - l[i]);
        ret[i] -= seg.prod(l[i], r[i]).m1;
    }
    return ret;
}

• Subtask 1: 0 / 4
• Subtask 2: 0 / 15
• Subtask 3: 17 / 17
• Subtask 4: 0 / 24
• Subtask 5: 0 / 40