Submission #129398

#	Time	Username	Problem	Language	Result	Execution time	Memory
129398		PeppaPig	Cake 3 (JOI19_cake3)	C++14	0 / 100	3 ms	2168 KiB

cake3

#include <bits/stdc++.h>

#define long long long
#define pii pair<int, int>
#define x first
#define y second

using namespace std;

const int N = 2e5+5;

vector<int> coord;

int get(int x) { return lower_bound(coord.begin(), coord.end(), x) - coord.begin() + 1; }

struct node {
    long sum, cnt;
    node *l, *r;
    node(long sum, long cnt, node *l, node *r) : sum(sum), cnt(cnt), l(l), r(r) { }
};

node* newleaf(long sum, long cnt) { 
    return new node(sum, cnt, nullptr, nullptr); 
}
node* newpar(node *l, node *r) {
    return new node(l->sum + r->sum, l->cnt + r->cnt, l, r);
}

node* build(int l = 1, int r = coord.size()) {
    if(l == r) return newleaf(0, 0);
    int mid = (l + r) >> 1;
    return newpar(build(l, mid), build(mid + 1, r));
}

node* update(long sum, int x, node *p, int l = 1, int r = coord.size()) {
    if(l == r) return newleaf(p->sum + sum, p->cnt + 1);
    int mid = (l + r) >> 1;
    if(x <= mid) return newpar(update(sum, x, p->l, l, mid), p->r);
    else return newpar(p->l, update(sum, x, p->r, mid + 1, r));
}

long query(int k, node *pa, node *pb, int l = 1, int r = coord.size()) {
    if(l == r) return pb->sum - pa->sum;
    long sum_r = pb->r->sum - pa->r->sum, cnt_r = pb->r->cnt - pa->r->cnt;
    int mid = (l + r) >> 1;
    if(cnt_r >= k) return query(k, pa->r, pb->r, mid + 1, r);
    else return sum_r + query(k - cnt_r, pa->l, pb->l, l, mid);
}

int n, m;
node* t[N];
pii v[N];

long ans[N];

void solve(int l, int r, int optl, int optr) {
    if(l > r) return;
    int mid = (l + r) >> 1, idx = optl;
    for(int i = max(mid + m - 1, optl); i <= optr; i++) {
        long now = query(m - 2, t[mid], t[i - 1]) + v[i].x + v[mid].x - 2ll * (v[i].y - v[mid].y);
        if(now > ans[mid]) ans[mid] = now, idx = i;
    }
    solve(l, mid - 1, optl, idx), solve(mid + 1, r, idx, optr);
}

int main() {
    fill_n(ans, N, -2e18);
    scanf("%d %d", &n, &m);
    for(int i = 1; i <= n; i++) {
        scanf("%d %d", &v[i].x, &v[i].y);
        coord.emplace_back(v[i].x);
    }
    sort(v + 1, v + n + 1, [&](const pii &a, const pii &b) {
        return a.y < b.y;
    });
    sort(coord.begin(), coord.end());
    coord.resize(unique(coord.begin(), coord.end()) - coord.begin());

    t[0] = build();

    for(int i = 1; i <= n; i++) t[i] = update(v[i].x, get(v[i].x), t[i-1]);

    solve(1, n - m + 1, 1, n);

    long ret = -2e18;
    for(int i = 1; i <= n; i++) ret = max(ret, ans[i]);
    printf("%lld\n", ret);

    return 0;
}

Compilation message (stderr)

cake3.cpp: In function 'int main()':
cake3.cpp:68:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d", &n, &m);
     ~~~~~^~~~~~~~~~~~~~~~~
cake3.cpp:70:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d", &v[i].x, &v[i].y);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 19
• Subtask 3: 0 / 76