oj.uz

Submission #260451

# Submission time Handle Problem Language Result Execution time Memory
260451 2020-08-10T09:39:04 Z georgerapeanu Printed Circuit Board (CEOI12_circuit) C++11
45 / 100
 100 ms 8900 KB 
#include <cstdio>
#include <algorithm>
#include <vector>
#include <set>

using namespace std;

int n;
pair<int,int> p[100005];
int ord[100005];
bool seen[100005];

const pair<int,int> origin = make_pair(0,0);

long long det(const pair<int,int> &a,const pair<int,int> &b,const pair<int,int> &c){
    return 1LL * a.first * (b.second - c.second) + 1LL * b.first * (c.second - a.second) + 1LL * c.first * (a.second - b.second);
}

pair<int,int> dir;
pair<int,int> nxt_dir;

struct segm_t{
    int i,j;
    long long a,b,c;

    segm_t(int i,int j){
        this->i = i;
        this->j = j;
        a = p[j].second - p[i].second;
        b = p[i].first - p[j].first;
        c = 1LL * p[j].first * p[i].second - 1LL * p[i].first * p[j].second;
    }

    bool operator < (const segm_t &other)const{
        ///-c/(a * dir.first + b * dir.second) < -other.c / (other.a * dir.first + other.b * dir.second);
        int sgn = (a * dir.first + b * dir.second > 0 ? 1:-1) * (other.a * dir.first + other.b * dir.second > 0 ? 1:-1);
        long long fst = sgn * c * (other.a * dir.first + other.b * dir.second);
        long long snd = sgn * other.c * (a * dir.first + b * dir.second);
        if(fst != snd){
            return fst > snd;
        }
        else{
            pair<int,int> dir = nxt_dir;
            int sgn = (a * dir.first + b * dir.second > 0 ? 1:-1) * (other.a * dir.first + other.b * dir.second > 0 ? 1:-1);
            long long fst = sgn * c * (other.a * dir.first + other.b * dir.second);
            long long snd = sgn * other.c * (a * dir.first + b * dir.second);
            if(fst != snd){
                return fst > snd;
            }
            else{
                return 1LL * p[j].second * p[j].second + 1LL * p[j].first * p[j].first < 1LL * p[other.j].first * p[other.j].first + 1LL * p[other.j].second * p[other.j].second;
            }
        }
    }

    bool is_good(const int &point)const{
        return det(p[i],p[j],p[point]) >= 0;
    }
};

set<segm_t> s;

bool cmp(const int &a,const int &b){
    return det(origin,p[a],p[b]) > 0;
}

int main(){

    scanf("%d",&n);

    for(int i = 1;i <= n;i++){
        scanf("%d %d",&p[i].first,&p[i].second);
        ord[i] = i;
    }

    sort(ord + 1,ord + 1 + n,cmp);

    vector<int> ans;


    for(int i = 1;i <= n;i++){
        dir = p[ord[i]];
        int j = i + 1;
        while(j <= n && cmp(ord[i],ord[j]) == 0){
            j++;
        }
        j--;
        nxt_dir = p[ord[j + 1]];
        for(int k = i;k <= j;k++){
            int curr = ord[k];
            int ant = (curr == 1 ? n:curr - 1);
            int nxt = (curr == n ? 1:curr + 1);
            ///TODO check colinearity of curr,nxt,ant to not erase stuff twice or smth            
            if(det(origin,p[curr],p[ant]) == 0){
                ;
            }
            else if(seen[ant]){
                s.erase(segm_t(ant,curr));
            }
            else{
                s.insert(segm_t(curr,ant));
            }
            if(det(origin,p[curr],p[nxt]) == 0){
                ;
            }
            else if(seen[nxt]){
                s.erase(segm_t(nxt,curr));
            }
            else{
                s.insert(segm_t(curr,nxt));
            }
        }

        int closest = -1;

        for(int k = i;k <= j;k++){
            if(closest == -1 || p[ord[k]].first < p[closest].first){
               closest = ord[k];  
            }
        }

        if(s.empty() == true){
            ans.push_back(closest);
        }
        else{
            if(s.begin()->is_good(closest)){
                ans.push_back(closest);
            }
        }

        for(int k = i;k <= j;k++){
            seen[ord[k]] = true;
        }
        i = j;
    }

    printf("%d\n",(int)ans.size());
   
    sort(ans.begin(),ans.end());

    for(auto it:ans){
        printf("%d ",it);
    }

    return 0;
}

Compilation message

circuit.cpp: In function 'int main()':
circuit.cpp:69:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
     ~~~~~^~~~~~~~~
circuit.cpp:72:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d",&p[i].first,&p[i].second);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
45.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 256 KB Output is correct
2 Correct 1 ms 384 KB Output is correct
3 Correct 2 ms 384 KB Output is correct
4 Correct 3 ms 512 KB Output is correct
5 Incorrect 11 ms 1280 KB Output isn't correct
6 Incorrect 11 ms 1152 KB Output isn't correct
7 Incorrect 22 ms 2176 KB Output isn't correct
8 Incorrect 8 ms 896 KB Output isn't correct
9 Correct 8 ms 896 KB Output is correct
10 Incorrect 12 ms 1148 KB Output isn't correct
11 Incorrect 12 ms 1152 KB Output isn't correct
12 Correct 12 ms 768 KB Output is correct
13 Incorrect 30 ms 2424 KB Output isn't correct
14 Correct 25 ms 1280 KB Output is correct
15 Correct 39 ms 1536 KB Output is correct
16 Correct 60 ms 2808 KB Output is correct
17 Execution timed out 143 ms 8900 KB Time limit exceeded
18 Execution timed out 24 ms 2816 KB Time limit exceeded (wall clock)
19 Execution timed out 23 ms 2816 KB Time limit exceeded (wall clock)
20 Execution timed out 141 ms 7672 KB Time limit exceeded