Submission #760679

#	Time	Username	Problem	Language	Result	Execution time	Memory
760679		AryanReddy	Aliens (IOI16_aliens)	C++14	0 / 100	1 ms	468 KiB

aliens

#undef local
#include <bits/stdc++.h>
#define all(v) v.begin(),v.end()
#define allr(v) v.rbegin(),v.rend()
#define fori(i,n) for(int i=0;i<n;i++)
#define ford(i,n) for(int i = n-1;i >= 0;i--)
#define pb push_back
#define ll long long int
//#define mod 998244353
#define pi pair<int,int>
#define pll pair<ll,ll>
#define mp make_pair
#define fi first
#define se second
#define printVector(v) fori(;,v.size()) {cout << v[i] << " ";} cout << "\n";
#pragma GCC optimize("O3")
std::mt19937 rng((unsigned int) std::chrono::steady_clock::now().time_since_epoch().count());
using namespace std;
struct LineContainer{
	vector<pll> lines;
	bool check(pll a1,pll a2,pll a3){
		assert(a1.fi <= a1.se && a2.fi <= a2.se);
		__int128_t c1 = a2.se - a1.se;
		c1 *= (a2.fi - a3.fi);
		__int128_t c2 = a3.se - a2.se;
		c2 *= a1.fi - a2.fi;
		return c1 >= c2;
	}
	void add(ll k,ll m){
		pll nw = {-k,-m};
		int sz;
		while(((sz = lines.size()) > 1) && check(lines[sz-2],lines[sz-1],nw)){
			lines.pop_back();
		}
		lines.push_back(nw);
	}
	ll get(ll x){
		ll res = 1e18;
		for(auto p:lines){
			res = min(res,-(p.fi * x + p.se));
		}
		return res;
	}
};
ll getAns(vector<pll> a,ll k){
    int n = a.size();
    sort(all(a),[&](pll x,pll y){
        return mp(x.fi,-x.se) < mp(y.fi,-y.se);
    });
    int ptr = a[0].se;
    vector<pll> b = {a[0]};
    for(int i= 1;i < n;i++){
        if(a[i].se <= ptr){
            continue;
        }
        b.push_back(a[i]);
        ptr = a[i].se;
    }
    a = b;
    n = a.size();
    vector<vector<ll> > dp(n+1,vector<ll> (k+1,1e18));
    vector<LineContainer> L(k+1);
    fori(i,k+1) dp[0][i] = 0;
    for(int j = 0;j < k;j++){
    	ll lt1 = a[0].fi;
    	ll c =  - 2 * lt1 + lt1 * lt1;
    	ll a = -2 * lt1;
    	L[j+1].add(a,c);
    }
    for(int i = 1;i <= n;i++){
        for(int j = 1;j <= k;j++){
            dp[i][j] = dp[i][j-1];
            ll ri=a[i-1].se;
            dp[i][j] = min(dp[i][j],L[j].get(ri) + ri * ri + 2*ri + 1);
            if(j < k && i < n){
            	ll lt1 = a[i].fi;
            	ll c = dp[i][j] - 2 * lt1 + lt1 * lt1;
            	ll rt = a[i-1].se;
            	ll tmp = max(0ll,rt - lt1 + 1);
            	c -= tmp * tmp;
            	ll a = -2 * lt1;
            	L[j+1].add(a,c);
            }
        }
    }
    return dp[n][k];
}
 
long long take_photos(int n, int m, int k, vector<int> r, vector<int> c){
    vector<pll> a;
    for(int i = 0;i < n;i++){
        int x = r[i];
        int y = c[i];
        a.pb(mp(min(x,y),max(x,y)));
    }
    sort(all(a));
    a.erase(unique(all(a)),a.end());
    ll ans = getAns(a,k);
    return ans;
}

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