Submission #58387

#	Time	Username	Problem	Language	Result	Execution time	Memory
58387		FLDutchman	Aliens (IOI16_aliens)	C++14	60 / 100	2074 ms	385036 KiB

aliens

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

typedef int INT;

#define pb push_back
#define FOR(i, l, r) for(int i = (l); i < (r); i++)
#define fst first
#define snd second
#define int long long

typedef vector<int> vi;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef long long ll;

const ll INF = 1e15;

struct line{
    int m, q;
    line (int M, int Q) {
        m = M;
        q = Q;
    }
    bool operator< (const line &l){
        return make_pair(m, q) < make_pair(l.m, l.q);
    }
    int eval(int x){
        return m*x+q;
    }
};

double intersect(const line &l1, const line &l2){
    return (long double) (l1.q - l2.q) / (l2.m - l1.m);
}

bool bad(const line &l1, const line &l2, const line &l3){
    return (l3.q-l2.q) * (l2.m - l1.m) < (l1.q - l2.q) * (l2.m - l3.m);
}

// MAX hull, slopes increasing
struct hull{
    deque<line> slopes;

    void insert(line l){
        while(slopes.size() >= 2 and bad(*prev(slopes.end(), 2), slopes.back(), l))  slopes.pop_back();
        slopes.push_back(l);
    }

    int get(int x){
        while(slopes.size() != 1 and slopes[0].eval(x) <= slopes[1].eval(x)) slopes.pop_front();
        return slopes[0].eval(x);
    }
};


vi C, R;
vii points;

int sqr(int x) {return x*x;}

long long take_photos(INT n, INT m, INT k, std::vector<INT> r, std::vector<INT> c) {
    FOR(i, 0, n) if(c[i] < r[i]) swap(r[i], c[i]);
    FOR(i, 0, n) points.pb({r[i], c[i]});

    points.pb({INF, INF});
    sort(points.begin(), points.end());
    FOR(i, 0, n){
        if(points[i].fst != points[i+1].fst){
            if(C.size() == 0 || points[i].snd > C.back()) {R.pb(points[i].fst); C.pb(points[i].snd);}
        }
    }
    //FOR(i, 0, C.size()){
    //    cout << R[i] << " " << C[i] << endl;
    //}
    vector<vi> dp;
    int N = C.size();
    dp.assign(N+1, vi(k+1, -1));
    FOR(i, 0, N) dp[i][0] = INF;
    FOR(K, 0, k+1) dp[N][K] = 0;
    FOR(K, 1, k+1){
        hull h;
        for(int i = N-1; i >= 0; i--){
            h.insert({2*(C[i] +1), -sqr(C[i]+1) - dp[i+1][K-1]});
            dp[i][K] = sqr(R[i]) - ( i == 0 ? 0 : sqr(max(0LL, C[i-1] + 1 - R[i])) ) - h.get(R[i]);
            //int mi = INF;
            //FOR(j, i+1, N+1) mi = min(mi, dp[j][K-1] + sqr(C[j-1]+1 - R[i]) - (i == 0 || C[i-1]+1-R[i] < 0 ? 0 : sqr(C[i-1]+1-R[i]) ) );
            //dp[i][K] = mi;
        }
    }
    //FOR(K, 0, k+1) {
    //    FOR(i, 0, N+1) cout << dp[i][K] << " ";
    //    cout<<endl;
    //}

    return dp[0][k];
}


/*
5 7 2
0 3
4 4
4 6
4 5
4 6

4 7 2
4 4
4 6
4 5
4 6

2 7 2
0 1
1 3

2 7 2
0 1
5 7
*/

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