Submission #942195

#	Time	Username	Problem	Language	Result	Execution time	Memory
942195		KG07	Aliens (IOI16_aliens)	C++17	0 / 100	1 ms	348 KiB

aliens

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

long long take_photos(int n, int m, int k, vector<int> r, vector<int> c) {
    priority_queue<pair<int, int>> q;
    for(int i = 0; i < n; i++){
        if(r[i] > c[i])q.push(make_pair(-c[i], r[i]));
        else q.push(make_pair(-r[i], c[i]));
    }
    vector<pair<int, int>> a;
    a.push_back(make_pair(-q.top().first, q.top().second));
    q.pop();
    while(!q.empty()){
        if(-q.top().first > a[a.size()-1].first && q.top().second > a[a.size()-1].second)a.push_back(make_pair(-q.top().first, q.top().second));
        q.pop();
    }
    long long L = 0LL, R = 1LL * m * m;
    while(true){
        long long C = (L+R+1)/2;
        vector<long long> b, d, x, y, z;
        vector<pair<int, int>> h;
        stack<long long> s;
        b.push_back(0LL);
        d.push_back(0LL);
        x.push_back(0LL);
        y.push_back(-2LL*(a[0].first-1));
        z.push_back(1LL*(a[0].first-1)*(a[0].first-1));
        h.push_back(make_pair(0, 0));
        //cout << b[0] << " " << x[0]-C << " " << y[0] << " " << z[0] << "\n";
        //cout << L << " " << C << " " << R << "\n";
        int e = 1;
        for(int i = 0; i < a.size(); i++){
            //cout << e-1 << "\n";
            b.push_back(1000000LL*m*m);
            d.push_back(0LL);
            x.push_back(C+1LL*a[i].second*a[i].second);
            y.push_back(-2LL*(a[i+1].first-1));
            z.push_back(1LL*(a[i+1].first-1)*(a[i+1].first-1)-max(0LL, 1LL*(a[i].second-a[i+1].first+1))*max(0LL, 1LL*(a[i].second-a[i+1].first+1)));

            for(int j = --e; j < h.size(); j++){
                if(b[h[j].first]+x[i+1]+y[h[j].first]*a[i].second+z[h[j].first] <= b[i+1])d[i+1] = d[h[j].first]+1;
                else break;
                e++;
                b[i+1] = min(b[i+1], b[h[j].first]+x[i+1]+y[h[j].first]*a[i].second+z[h[j].first]);
            }
            while(h.size() > 0 && b[h[h.size()-1].first]+y[h[h.size()-1].first]*h[h.size()-1].second+z[h[h.size()-1].first] >=b[i+1]+y[i+1]*h[h.size()-1].second+z[i+1])h.pop_back();
            if(h.size() == 0)h.push_back(make_pair(i+1, 0));
            else h.push_back(make_pair(i+1, (b[i+1]+z[i+1]-b[h[h.size()-1].first]-z[h[h.size()-1].first])/(y[h[h.size()-1].first]-y[i+1])+1));
            e = min(e, (int) h.size());
            //for(pair<int, int> t: h)cout << t.first << " " << y[t.first] << " " << z[t.first]+b[t.first] << " " << t.second << "\n";
            //cout << b[i+1] << " " << x[i+1] << " " << y[i+1] << " " << z[i+1] << " " << d[i+1] << "\n";
        }
        if(L == R)return b[a.size()]-C*min(1LL*k, d[a.size()]);
        if(d[a.size()] < k)R = (L+R)/2;
        else L = C;
    }

    return 0;
}

Compilation message (stderr)

aliens.cpp: In function 'long long int take_photos(int, int, int, std::vector<int>, std::vector<int>)':
aliens.cpp:33:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int>, std::allocator<std::pair<int, int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   33 |         for(int i = 0; i < a.size(); i++){
      |                        ~~^~~~~~~~~~
aliens.cpp:41:32: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int>, std::allocator<std::pair<int, int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   41 |             for(int j = --e; j < h.size(); j++){
      |                              ~~^~~~~~~~~~

• Subtask 1: 0 / 4
• Subtask 2: 0 / 12
• Subtask 3: 0 / 9
• Subtask 4: 0 / 16
• Subtask 5: 0 / 19
• Subtask 6: 0 / 40