Submission #646541

#	Time	Username	Problem	Language	Result	Execution time	Memory
646541		kith14	Lightning Rod (NOI18_lightningrod)	C++17	100 / 100	1781 ms	229556 KiB

Main

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

#define ll int
#define db double
#define pairll pair<ll,ll>
#define lpairll pair<ll,pairll>

#define repp(i,a,b) for (ll i = a; i <= b; i++)
#define repz(i,a,b) for (ll i = a; i < b; i++)
#define repm(i,a,b) for (ll i = a; i >= b; i--)
#define fr first
#define sc second
#define x first
#define y second
#define mp make_pair
#define pb push_back

const ll N = 5e5+5, MOD = 1e9+7;
ll tc = 1, n, m, xr[N], yr[N];
string s, s1, s2, ye = "YA", no = "TIDAK";

void input(){
  cin >> n;
}

//check if a can consume b
bool eat(pairll a, pairll b){
  if (a == b) return 1;
  if (a.sc > b.sc){
    ll df = a.sc-b.sc;
    if (a.fr-df <= b.fr && b.fr <= a.fr+df) return 1;
  } 
  return 0;
}

void solve(){
  vector<pairll> v;
  //note that xr is increasing
  repp(i,1,n){
    ll xr, yr;
    cin >> xr >> yr;
    //while current point can consume other points
    while(v.size() && eat(mp(xr,yr),v.back())){
      v.pop_back();
    }
    //if empty or the last point cannot consume current point
    if (v.empty() || !eat(v.back(),mp(xr,yr))) v.pb(mp(xr,yr));
  }
  cout << v.size() << endl;
  //for (auto i : v) cout << i.fr << " " << i.sc << endl;
}

int main(){
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  cout.tie(NULL);
  //cin >> tc;
  while(tc--){
    input();
    solve();
  }
}

• 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: 20 / 20