Submission #349460

#	Time	Username	Problem	Language	Result	Execution time	Memory
349460		tengiz05	Aliens (IOI16_aliens)	C++17	41 / 100	755 ms	75884 KiB

aliens

#include "aliens.h"
#ifndef EVAL
#include "grader.cpp"
#endif
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define pii pair<int,int>
#define all(x) x.begin(), x.end()
#define ff first
#define ss second
ll n, m, k;
ll dp[5005][5005];
bool cmp(pii &x, pii &y){
	if(x.ff != y.ff)return x.ff < y.ff;
	return x.ss < y.ss;
}
vector<pii> a;
ll sq(ll t){
	return t*t;
}
ll cost(int i, int j){
	assert(j < a.size());
	int r1=a[i].ff, c1=a[i].ss;
	int r2=a[j].ff, c2=a[j].ss;
	ll r = min(r1,r2), c = max(c1,c2);
	ll di = c-r+1;
	ll total = sq(di);
	if(i==0 || a[i-1].ss <= c-di)return total;
	return total - sq(a[i-1].ss - (c-di));
}
void divide_and_conquer_please(int K, int l, int r, int optl, int optr){
	if(l > r)return;
	int mid = (l+r)>>1;
	pair<ll,int> best = {(ll)1e18, -1};
	for(int i=optl;i<=min(optr,mid);i++){
		best = min(best, {dp[i-1][K-1] + cost(i,mid), i});
	}dp[mid][K] = best.ff;
	int opt = best.ss;
	divide_and_conquer_please(K,l,mid-1,optl,opt);
	divide_and_conquer_please(K,mid+1,r,opt,optr);
}
ll take_photos(int Ni, int Mi, int Ki, vector<int> r, vector<int> c){
	n = Ni, m = Mi, k = Ki;
	vector<pii> v;
	for(int i=0;i<n;i++){
		if(r[i] > c[i])swap(r[i],c[i]);
		v.push_back({r[i],c[i]});
	}sort(all(v), cmp);
	
	
	//clearing some unneeded points
	vector<pii> pre_taza, finals;
	for(int i=0;i<n;i++){
		while(i+1 < n && v[i+1].ff == v[i].ff)i++;
		pre_taza.push_back(v[i]);
	}
	n = pre_taza.size();
	int mx = 0;
	for(int i=0;i<n;i++){
		mx = max(mx, pre_taza[i].ss);
		finals.push_back(pre_taza[i]);
		while(i+1 < n && pre_taza[i+1].ss <= mx)i++;
	}a.push_back({-1,-1});
	for(auto x : finals)a.push_back(x);
	n = finals.size();
	//stopping
	
	k = min(k,n);
	for(int i=1;i<=n;i++){
		for(int j=1;j<=k;j++)dp[i][j] = 1e18;
	}
	for(int i=1;i<=n;i++){
		dp[i][1] = cost(1,i);
	}
	for(int i=2;i<=k;i++){
		divide_and_conquer_please(i,1,n,1,n);
	}
	return dp[n][k];
}

/*

5 7 2
0 3
4 4
4 6
4 5
4 6



2 100 1
1 4
4 1



*/

Compilation message (stderr)

In file included from /usr/include/c++/9/cassert:44,
                 from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:33,
                 from aliens.cpp:5:
aliens.cpp: In function 'll cost(int, int)':
aliens.cpp:23:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   23 |  assert(j < a.size());
      |         ~~^~~~~~~~~~

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