Submission #364185

#	Time	Username	Problem	Language	Result	Execution time	Memory
364185		cpp219	Cake 3 (JOI19_cake3)	C++98	100 / 100	1925 ms	13548 KiB

cake3

#include <bits/stdc++.h>

using namespace std;

#define sz(x) (int)x.size()
#define fi first
#define se second

typedef long long lli;
typedef pair<int, int> pii;

const int maxn = 2e5 + 5;
const lli inf = 1e18;

int n, m;
pii cakes[maxn];

vector<int> vals;

lli f[maxn];

struct segment_tree
{
    lli total[maxn * 4];
    int cnt[maxn * 4];

    void update(int x, int l, int r, int p, int k)
    {
        if(l == r)
        {
            total[x] += vals[l - 1] * k;
            cnt[x] += k;
            return;
        }
        int mid = (l + r) / 2;
        if(p <= mid) update(x * 2, l, mid, p, k);
        else update(x * 2 + 1, mid + 1, r, p, k);
        total[x] = total[x * 2] + total[x * 2 + 1];
        cnt[x] = cnt[x * 2] + cnt[x * 2 + 1];
    }

    lli get(int x, int l, int r, int k)
    {
        if(l == r) return vals[l - 1] * 1LL * min(k, cnt[x]);
        int mid = (l + r) / 2;
        if(cnt[x * 2 + 1] <= k)
            return total[x * 2 + 1] + get(x * 2, l, mid, k - cnt[x * 2 + 1]);
        else return get(x * 2 + 1, mid + 1, r, k);
    }
} tree;

void read_input()
{
    cin >> n >> m;
    for(int i = 1; i <= n; ++i)
        cin >> cakes[i].fi >> cakes[i].se;
}

void init()
{
    sort(cakes + 1, cakes + n + 1, [](pii p, pii q)
         {
             return p.se < q.se;
         });
    for(int i = 1; i <= n; ++i)
        vals.push_back(cakes[i].fi);
    sort(vals.begin(), vals.end());
    vals.erase(unique(vals.begin(), vals.end()), vals.end());
    for(int i = 1; i <= n; ++i)
        cakes[i].fi = lower_bound(vals.begin(), vals.end(), cakes[i].fi) - vals.begin() + 1;
}

lli query(int l, int r)
{
    static int curl = 1, curr = 0;
    while(curr < r)
    {
        ++curr;
        tree.update(1, 1, sz(vals), cakes[curr].fi, 1);
    }
    while(curr > r)
    {
        tree.update(1, 1, sz(vals), cakes[curr].fi, -1);
        --curr;
    }
    while(curl > l)
    {
        --curl;
        tree.update(1, 1, sz(vals), cakes[curl].fi, 1);
    }
    while(curl < l)
    {
        tree.update(1, 1, sz(vals), cakes[curl].fi, -1);
        ++curl;
    }
    return tree.get(1, 1, sz(vals), m);
}

void dnc(int l, int r, int optl, int optr)
{
    if(l > r) return;
    int mid = (l + r) / 2;
    lli best = -inf;
    int opt = 0;
    for(int i = max(mid + m - 1, optl); i <= optr; ++i)
    {
        lli k = query(mid, i) - 2LL * (cakes[i].se - cakes[mid].se);
        if(k > best)
        {
            best = k;
            opt = i;
        }
    }
    f[mid] = best;
    dnc(l, mid - 1, optl, opt);
    dnc(mid + 1, r, opt, optr);
}

void solve()
{
    dnc(1, n - m + 1, 1, n);
    lli ans = -inf;
    for(int i = 1; i <= n - m + 1; ++i)
        ans = max(ans, f[i]);
    cout << ans << '\n';
}

int main()
{
    #define task "test"
    if (fopen(task".INP","r")){
        freopen(task".INP","r",stdin);
        freopen(task".ans","w",stdout);
    }
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    read_input();
    init();
    solve();
}

Compilation message (stderr)

cake3.cpp: In function 'int main()':
cake3.cpp:134:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  134 |         freopen(task".INP","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
cake3.cpp:135:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  135 |         freopen(task".ans","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 19 / 19
• Subtask 3: 76 / 76