Submission #396392

#	Time	Username	Problem	Language	Result	Execution time	Memory
396392		4fecta	Road Construction (JOI21_road_construction)	C++17	0 / 100	10058 ms	66772 KiB

road_construction

#include <bits/stdc++.h>

using namespace std;
#define ll long long
#define int ll
#define ld long double
#define pii pair<int, int>
#define f first
#define s second
#define boost() cin.tie(0), cin.sync_with_stdio(0)

const int MN = 750005;

int n, k, x, y, bit[MN];
pii a[MN];

void upd(int x, int val) {
    for (int i = x; i < MN; i += i & -i) bit[i] += val;
}

int qry(int x) {
    int ret = 0;
    for (int i = x; i > 0; i -= i & -i) ret += bit[i];
    return ret;
}

int cost(pii p, pii q) {
    return max(abs(p.f - q.f), abs(p.s - q.s));
}

int count(int d) {
    int ret = 0;
    memset(bit, 0, sizeof(bit));
    vector<int> ys;
    for (int i = 1; i <= n; i++) {
        ys.push_back(a[i].s);
        ys.push_back(a[i].s - d);
        ys.push_back(a[i].s + d);
    }
    sort(ys.begin(), ys.end());
    ys.erase(unique(ys.begin(), ys.end()), ys.end());
    map<int, int> mp;
    for (int i = 0; i < ys.size(); i++) mp[ys[i]] = i + 1;
    int id = 1;
    for (int i = 1; i <= n; i++) {
        while (a[i].f - a[id].f > d) upd(mp[a[id].s], -1), id++;
        ret += qry(mp[a[i].s + d]) - qry(mp[a[i].s - d] - 1);
        //printf("lol %lld %lld\n", mp[a[i].s + d], mp[a[i].s - d]);
        upd(mp[a[i].s], 1);
    }
    return ret;
}

int32_t main() {
    boost();

    cin >> n >> k;
    for (int i = 1; i <= n; i++) {
        cin >> x >> y;
        a[i] = {x + y, x - y};
        //printf("%lld %lld\n", a[i].f, a[i].s);
    }
    sort(a + 1, a + n + 1);
    int lo = 1, hi = 1e10, mid;
    while (lo < hi) {
        mid = (lo + hi) >> 1;
        if (count(mid) >= k) hi = mid;
        else lo = mid + 1;
    }
    //printf("cnt %lld\n", count(2));
    printf("%lld\n", lo);

    return 0;
}

Compilation message (stderr)

road_construction.cpp: In function 'long long int count(long long int)':
road_construction.cpp:43:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   43 |     for (int i = 0; i < ys.size(); i++) mp[ys[i]] = i + 1;
      |                     ~~^~~~~~~~~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 6
• Subtask 3: 0 / 7
• Subtask 4: 0 / 20
• Subtask 5: 0 / 27
• Subtask 6: 0 / 35