Submission #416205

#	Time	Username	Problem	Language	Result	Execution time	Memory
416205		alishahali1382	Group Photo (JOI21_ho_t3)	C++14	100 / 100	370 ms	67388 KiB

Main

#include <bits/stdc++.h>
#pragma GCC optimize ("O2,unroll-loops")
//#pragma GCC optimize("no-stack-protector,fast-math")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<pii, int> piii;
typedef pair<ll, ll> pll;
#define debug(x) cerr<<#x<<'='<<(x)<<endl;
#define debugp(x) cerr<<#x<<"= {"<<(x.first)<<", "<<(x.second)<<"}"<<endl;
#define debug2(x, y) cerr<<"{"<<#x<<", "<<#y<<"} = {"<<(x)<<", "<<(y)<<"}"<<endl;
#define debugv(v) {cerr<<#v<<" : ";for (auto x:v) cerr<<x<<' ';cerr<<endl;}
#define all(x) x.begin(), x.end()
#define pb push_back
#define kill(x) return cout<<x<<'\n', 0;

const int inf=1000000010;
const ll INF=1000000000000001000LL;
const int mod=1000000007;
const int MAXN=5010, LOG=20;

int n, m, k, u, v, x, y, t, a, b;
int A[MAXN], B[MAXN];
int cnt[MAXN][MAXN];
int dp[MAXN];

inline int C2(int x){ return x*(x-1)/2;}

int main(){
	ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
	//freopen("input.txt", "r", stdin);
	//freopen("output.txt", "w", stdout);
	cin>>n;
	for (int i=1; i<=n; i++) cin>>A[i], B[A[i]]=i;
	for (int r=1; r<=n; r++){
		for (int l=r-1; l; l--){
			cnt[l][r]=cnt[l+1][r]+cnt[l][r-1]-cnt[l+1][r-1]+(B[l]>B[r]);
		}
	}
	for (int i=1; i<=n; i++){
		dp[i]=C2(i)-cnt[1][i] + cnt[1][n]-cnt[1][i]-cnt[i+1][n];
		for (int j=1; j<i; j++){
			int cost1=C2(i-j)-cnt[j+1][i];  // (j, i]
			int cost2=cnt[j+1][n]-cnt[j+1][i]-cnt[i+1][n];
			dp[i]=min(dp[i], dp[j] + cost1 + cost2);
		}
	}
	cout<<dp[n]<<"\n";
	
	return 0;
}

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