Submission #544459

#	Time	Username	Problem	Language	Result	Execution time	Memory
544459		ac2hu	Lightning Rod (NOI18_lightningrod)	C++14	100 / 100	1888 ms	262144 KiB

Main

#include <bits/stdc++.h>
#ifdef DEBUG
#include "../templates/debug.h"
#else 
#define deb(x...)
#endif
using namespace std;
void setIO(string name) {
	#ifdef DEBUG
	#else 
	ios_base::sync_with_stdio(0); cin.tie(0);
	freopen((name+".in").c_str(),"r",stdin);
	freopen((name+".out").c_str(),"w",stdout);
	#endif
}
signed main() {
    iostream::sync_with_stdio(false);
    cin.tie(nullptr);cout.tie(nullptr);
    int n;cin >> n;
    vector<pair<int,int>> a(n);
    for(auto &e : a){
        cin >> e.first >> e.second;
    }
    auto fit = [&](pair<int,int> a,pair<int,int> b) -> bool{
        // if b can't fit a 
        return (abs(b.first  - a.first) <= abs(b.second - a.second));
    };
    auto better = [&](pair<int,int> a, pair<int,int> b) -> bool{
        if(a.first + a.second > b.first + b.second)
            return true;
        return false;
    };
    vector<pair<int,int>> st;
    st.push_back(a[0]);
    for(int i = 1;i<n;i++){
        while(st.size() > 0 && fit(a[i], st.back()) && better(a[i], st.back())){
            st.pop_back();
        }
        if(st.size() == 0 || !fit(a[i], st.back())){//(!fit(a[i], st.back()) && !better(st.back(), a[i]))){
            st.push_back(a[i]);
        }
        deb(st);
    }
    // cout << fit(a[n - 1], st.back()) << " " << better(st.back(), a[n - 1]) << "\n";
    cout << st.size() << "\n";
}

Compilation message (stderr)

lightningrod.cpp: In function 'void setIO(std::string)':
lightningrod.cpp:12:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   12 |  freopen((name+".in").c_str(),"r",stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lightningrod.cpp:13:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   13 |  freopen((name+".out").c_str(),"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