Submission #770913

#	Time	Username	Problem	Language	Result	Execution time	Memory
770913		joshuaZ	Road Construction (JOI21_road_construction)	C++17	0 / 100	10048 ms	51272 KiB

road_construction

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll,ll> pll;
const int mxN = 250002;

int n, k;
multiset<ll> path;
pll a[mxN];


bool solve(ll d){
    set<pll> st;
    for (int i = 1, j = 1; i <= n; i++){
        while (a[i].first - a[j].first > d){
            st.erase({a[j].second, a[j].first});
            j++;
        }
        auto l = st.lower_bound({a[i].second - d, -1e10});
        auto r = st.upper_bound({a[i].second + d, -1e10});
        for (auto it = l; it != r; it++){
            path.insert(max(abs((*it).second - a[i].first), abs((*it).first - a[i].second)));
            ll b = max(abs((*it).second - a[i].first), abs((*it).first - a[i].second));
            assert(b <= d);
            if (path.size() >= 4 * mxN){
                return true;
            }
        }
        st.insert({a[i].second, a[i].first});
    }

    if (path.size() >= k){
        return true;
    } else {
        return false;
    }
}

int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);

    cin >> n >> k;
    //xi + yi - (xj + yj) <= val
    //xi - yi - (xj - yj) <= val
    for (int i = 1; i <= n; i++){
        ll x, y; cin >> x >> y;
        a[i].first = x + y;
        a[i].second = x - y;
    }
    sort(a + 1, a + 1 + n);

    ll lo = 1, hi = 2e9, ans = -1;
    while (lo <= hi){
        ll mid = lo + (hi - lo) / 2;
        if (solve(mid)){
            ans = mid;
            hi = mid - 1;
        } else {
            lo = mid + 1;
        }
        path.clear();
    }

    solve(ans);

    int c = 1;
    for (auto &x : path){
        cout << x << '\n';
        if (c++ >= k){
            break;
        }
    }
}

Compilation message (stderr)

road_construction.cpp: In function 'bool solve(ll)':
road_construction.cpp:32:21: warning: comparison of integer expressions of different signedness: 'std::multiset<long long int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   32 |     if (path.size() >= k){
      |         ~~~~~~~~~~~~^~~~

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