Submission #412990

#	Time	Username	Problem	Language	Result	Execution time	Memory
412990		Chaska	Group Photo (JOI21_ho_t3)	C++11	100 / 100	402 ms	580 KiB

Main

#include <bits/stdc++.h> 
#define pb push_back
#define sp " "
#define sl "\n"
#define fi first
#define se second
#define mp make_pair
#define sz(a) ((int)a.size())
#define all(a) a.begin(),a.end()
#define rev(a) reverse(a.begin(),a.end())
#define PI 3.141592
#define fo(i,n) for (int i=0;i<n;i++)
#define fofo(i,n,j,m) for (int i=0;i<n;i++) for (int j=0;j<m;j++) 
 
using namespace std;
 
typedef long long ll;
typedef pair<ll,ll> ii;
typedef pair<int,ii> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
const int N=5e3+5,mod=1e9+7;

int n,a[N];
ll dp[N];
int st[N];
int g[N];
vi aux;
int tam;
void add(int u)
{
	while (u<=tam) {
		st[u]++;
		u += u&(-u);
	}
	return;
}
int get(int u)
{
	int r = 0;
	while (u>0) {
		r += st[u];
		u -= u&(-u);
	}
	return r;
}
int main() { 
	cin.tie(0); cout.tie(0); 
	ios_base::sync_with_stdio();
	cin >> n;
	for (int i=0;i<n;i++) cin >> a[i];
	dp[0] = dp[1] = 0;
	for (int i=2;i<=n;i++) dp[i] = 1e15;
	for (int i=0;i<n;i++) g[a[i]] = i;
	for (int i=n;i>=1;i--) {
		int p1,p2;
		p2 = get(g[i]-1);
	}
	for (int i=2;i<=n;i++) {
		aux.clear();
		for (int j=0;j<n;j++) if (a[j]<=i) aux.push_back(a[j]);
		tam = i;
		int p=0;
		long long res = 0;
		for (int u : aux) g[u] = ++p;
		for (int j=0;j<=n;j++) st[j] = 0;
		for (int j=i;j>=1;j--) {
			
			int  k = get(g[j]-1);
			res += i-g[j]-k;
			dp[i] = min(dp[i],dp[j-1]+res);
			add(g[j]);
		}
		//cout << dp[i] << " ";
	}
	cout << dp[n];
	return 0;
}

// Recuerda limites 
// Recuerda casos especiales

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:56:7: warning: unused variable 'p1' [-Wunused-variable]
   56 |   int p1,p2;
      |       ^~
Main.cpp:56:10: warning: variable 'p2' set but not used [-Wunused-but-set-variable]
   56 |   int p1,p2;
      |          ^~

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 32 / 32
• Subtask 4: 20 / 20
• Subtask 5: 36 / 36