Submission #948012

#	Time	Username	Problem	Language	Result	Execution time	Memory
948012		Cadoc	Lightning Rod (NOI18_lightningrod)	C++14	100 / 100	1351 ms	252020 KiB

Main

/*
    Author: Cadocx
    Codeforces: https://codeforces.com/profile/Kadoc
    VNOJ: oj.vnoi.info/user/Cadoc
*/

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

// input/output
#define fastIO ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0)
#define el cout << '\n'
#define execute cerr << "Time elapsed: " << (1.0 * clock() / CLOCKS_PER_SEC) << "s"
// #pragma GCC optimize("O2")
// #pragma GCC optimize("Ofast")
// #pragma GCC target("avx,avx2,fma")
//data type
#define ll long long
#define ull unsigned long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define piv pair<int, vector<int>>
#define vi vector<int>
#define vl vector<ll>
#define vc vector<char>
//STL
#define sz(x) (int)(x).size()
#define for1(i,l,r) for(auto i = l; i <= r; i++)
#define for2(i,r,l) for(auto i = r; i >= l; i--)
#define forin(i,a) for(auto i : a)
#define pb push_back
#define eb emplace_back
#define pf push_front
#define all(x) (x).begin(), (x).end()
#define fi first
#define se second
//bitmask
#define bitcnt(n) __builtin_popcount(n)
#define mask(i) (1 << (i))
#define bit(n, i) (((n) >> (i)) & 1)
#define set_on(n, i) ((n) | mask(i))
#define set_off(n, i) ((n) & ~mask(i))
//constant
#define N 10000005
#define MOD 1000230007
#define INF 0x3f3f3f3f
#define LINF 0x3f3f3f3f3f3f3f3f
#define base 31
#define Kadoc 0

int n, x[N], y[N];
vector<int> v;

bool cover(int i, int j){
    return abs(x[i] - x[j]) <= y[i] - y[j];
}

void solve(){
    cin >> n;
    for(int i=1; i<=n; ++i){
        cin >> x[i] >> y[i];
        if(v.size() && cover(v.back(), i)) continue;
        while(v.size() && cover(i, v.back())) v.pop_back();
        v.pb(i);
    }

    cout << v.size(); el;
}

int main(){
    #define NAME "TASK"
    if(fopen(NAME".inp", "r")){
        freopen(NAME".inp", "r", stdin);
        freopen(NAME".out", "w", stdout);
    }

    fastIO;
    
    if(Kadoc){
        int tc; cin >> tc;
        while(tc--){
            solve();
        }
    } else solve();
}

Compilation message (stderr)

lightningrod.cpp: In function 'int main()':
lightningrod.cpp:73:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   73 |         freopen(NAME".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
lightningrod.cpp:74:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   74 |         freopen(NAME".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• 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