Submission #340313

#	Time	Username	Problem	Language	Result	Execution time	Memory
340313		achibasadzishvili	Aliens (IOI16_aliens)	C++14	100 / 100	269 ms	9820 KiB

aliens

#include<bits/stdc++.h>
#define ll long long
#define f first
#define s second
#define pb push_back
#define mp make_pair
using namespace std;
ll dp[200005],raod[200005],tana[200005],a[200005],b[200005],n,m;
struct line {
    ll m,c,ind;
    ll calc(ll x){
        return m * x + c;
    }
    long double inter(line l){
        return (long double)(c - l.c) / (l.m - m);
    }
};
deque<line>q;
void insertQ(line x){
    while(q.size() >= 2 && q.back().inter(x) <= q.back().inter(q[(int)q.size() - 2]))
        q.pop_back();
    q.push_back(x);
}
pair<ll,ll> calcQ(ll x){
    while(q.size() >= 2 && q[0].calc(x) > q[1].calc(x))
        q.pop_front();
    return mp(q[0].calc(x) , q[0].ind);
}
pair<ll,ll>P(ll x){
    dp[1] = (b[1] - a[1] + 1) * (b[1] - a[1] + 1) - tana[1] + x;
    while(q.size())q.pop_back();
    line l;
    l.c = a[1] * a[1] - 2 * a[1];
    l.m = -2 * a[1];
    l.ind = 0;
    raod[1] = 1;
    insertQ(l);
    for(int i=2; i<=n; i++){
        pair<ll,ll> p = calcQ(b[i]);
        ll mn = p.f + 2 * b[i] + b[i] * b[i] + 1;
        ll nex = dp[i - 1] + (b[i] - a[i] + 1) * (b[i] - a[i] + 1);
        raod[i] = p.s + 1;
        if(nex < mn){
            mn = nex;
            raod[i] = raod[i - 1] + 1;
        }
        dp[i] = mn - tana[i] + x;
        l.m = -2 * a[i];
        l.c = dp[i - 1] + a[i] * a[i] - 2 * a[i];
        l.ind = raod[i - 1];
        insertQ(l);
    }
    //cout << x << " " << raod[n] << " " << dp[n] << '\n';
    return mp(raod[n] , dp[n]);
}
ll take_photos(int N,int M,int k,vector<int>R,vector<int>C){
    n = N;
    m = M;
    vector<pair<ll,ll> >w;
    ll newn = 0;
    for(int i=0; i<n; i++){
        if(R[i] > C[i])
            swap(R[i] , C[i]);
        w.pb(mp(R[i] , -C[i]));
    }
    sort(w.begin() , w.end());
    ll mxc = -1;
    for(int i=0; i<w.size(); i++){
        if(mxc >= -w[i].s)continue;
        else {
            newn++;
            a[newn] = w[i].f;
            b[newn] = -w[i].s;
        }
        mxc = max(mxc , -w[i].s);
    }
    n = newn;
    /*
    // checking all of this
    {
        cout << n << '\n';
        for(int i=1; i<=n; i++){
            cout << a[i] << " " << b[i] << '\n';
        }
        cout << "First Check: Done\n";
    }
    */
    for(int i=1; i<n; i++)
        if(a[i + 1] <= b[i])
            tana[i] = (b[i] - a[i + 1] + 1) * (b[i] - a[i + 1] + 1);
    ll l = 0,r = 2 * m * m ,mid,ans = -1;
    k = min((ll)k , n);
    while(r >= l){
        mid = (l + r) / 2;
        pair<ll,ll>got = P(mid);
        if(got.f <= k){
            r = mid - 1;
            ans = got.s - k * mid;
        }
        else {
            l = mid + 1;
        }
    }
    return ans;
}

Compilation message (stderr)

aliens.cpp: In function 'long long int take_photos(int, int, int, std::vector<int>, std::vector<int>)':
aliens.cpp:68:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   68 |     for(int i=0; i<w.size(); i++){
      |                  ~^~~~~~~~~

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