Submission #830844

#	Time	Username	Problem	Language	Result	Execution time	Memory
830844		exodus_	Lightning Rod (NOI18_lightningrod)	C++14	44 / 100	2058 ms	262056 KiB

Main

#include<bits/stdc++.h>
#define ll long long
#define fi first
#define se second
using namespace std;
const int nmax = 1e7+7;
struct point {
    int x;
    int y;
    int dex;
};
bool cmp(point &a, point&b) {
    return (a.y > b.y);
}
int par[nmax];
bool soada[nmax] = {false};
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int N;
    cin >> N;
    vector<point>tik(N+1);
    bool sub1=true;
    bool sub6=true;
    int hit=0;
    int baw=0;
    for(int i=1; i<=N; i++) par[i]=i;
    for(int i=0; i<N; i++) {
        cin >> tik[i].x >> tik[i].y;
        if(i>0 && tik[i].x!=tik[i-1].x) hit++;
        if(tik[i].y != 1) sub1=false;
        if(tik[i].y > 1 || tik[i].x!=i+1) sub6=false;
    }
    if(sub1==true) {
        cout << hit+1 << endl;
        return 0;
    }
    if(sub6==true) {
        int i=1;
        while(i<N) {
            if(tik[i].y==1) {
                if(tik[i-1].y==0 && soada[i-1]==false) {
                    baw++;
                }
                if(i+1<N && tik[i+1].y==0) {
                    baw++;
                    soada[i+1]=true;
                }
            }
            i++;
        }
        int cost = N-baw;
        cout << cost << endl;
        return 0;
    }
    sort(tik.begin(), tik.end(), cmp);
    for(int i=0; i<N; i++) {
        tik[i].dex = i+1;
    }
    vector<int>dafter;
    while(!tik.empty()) {
        dafter.push_back(0);
        for(int i=1; i<tik.size(); i++) {
            if(abs(tik[0].x - tik[i].x) <= tik[0].y-tik[i].y) {
                par[tik[i].dex] = tik[0].dex;
                //cout << "par[" << tik[i].dex << "] = " << tik[0].dex << endl;
                dafter.push_back(i);
            }
        }
        int kur = 0;
        for(int j=0; j<dafter.size(); j++) {
            //cout << "dafter " << dafter[j] << endl;
            tik.erase(tik.begin()+dafter[j]-kur);
            kur++;
        }
        dafter.clear();
    }
    int cost = 0;
    for(int i=1; i<=N; i++) {
        if(soada[par[i]]==false) {
            cost++;
            soada[par[i]]=true;
        }
    }
    cout << cost << endl;
    return 0;
}

Compilation message (stderr)

lightningrod.cpp: In function 'int main()':
lightningrod.cpp:64:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<point>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   64 |         for(int i=1; i<tik.size(); i++) {
      |                      ~^~~~~~~~~~~
lightningrod.cpp:72:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   72 |         for(int j=0; j<dafter.size(); j++) {
      |                      ~^~~~~~~~~~~~~~

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