Submission #692886

#	Time	Username	Problem	Language	Result	Execution time	Memory
692886		saayan007	Lightning Rod (NOI18_lightningrod)	C++17	80 / 100	2023 ms	262144 KiB

Main

#include <bits/stdc++.h>
using namespace std;

using ll = long long;
using pi = pair<int, int>;
using pl = pair<ll, ll>;
using vi = vector<int>;
using vl = vector<ll>;
using vpi = vector<pi>;
using vpl = vector<pl>;

#define fur(i, a, b) for(ll i = a; i <= (ll) b; ++i)
#define ruf(i, a, b) for(ll i = a; i >= (ll) b; --i)
#define fr first
#define sc second
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define nl "\n"

const ll inf = 1e12L;

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

    ll n;
    cin >> n;

    pl a[n + 2];
#define x first
#define y second
    fur(i, 1, n) {
        cin >> a[i].x >> a[i].y;
    }
    a[0] = a[n + 1] = {0, 0};
    sort(a + 1, a + n + 1);

    bool under[n + 1] = {};
    ll mx = -inf;
    ruf(i, n, 1) {
        if(a[i].y - a[i].x <= mx) {
            under[i] = 1;
        } else {
            mx = a[i].y - a[i].x;
        }
    }

    mx = -inf;
    fur(i, 1, n) {
        if(a[i].y + a[i].x <= mx) {
            under[i] = 1;
        } else {
            mx = a[i].y + a[i].x;
        }
    }

    ll ans = n;
    fur(i, 1, n) {
        if(under[i])
            --ans;
    }
    cout << ans <<nl;
}

• Subtask 1: 4 / 4
• Subtask 2: 7 / 7
• Subtask 3: 12 / 12
• Subtask 4: 21 / 21
• Subtask 5: 26 / 26
• Subtask 6: 10 / 10
• Subtask 7: 0 / 20