Submission #534898

#	Time	Username	Problem	Language	Result	Execution time	Memory
534898		Paul_Liao_1457	Group Photo (JOI21_ho_t3)	C++14	100 / 100	507 ms	244524 KiB

Main

// 還要更強
#include<iostream>
#include<queue>
#include<set>
#include<map>
#include<iomanip>
#include<math.h>
#include<cstring>
#include<stack>
#include<string.h>
#include<random>
#include<algorithm>
#include<vector>

#define ll long long
#define FOR(i,a,b) for(int i=a;i<b;i++)
#define REP(i,a,b) for(int i=a;i>=b;i--)
#define S second
#define F first
#define INF (ll)(3e18)
#define pb push_back
#define AC ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);

using namespace std;

int n,h[5005],pos[5005],pre[2][5005][5005],dp[5005];
bool ni[2][5005][5005];

signed main(){
    AC;
    cin>>n;
    FOR(i,1,n+1){
        cin>>h[i]; pos[h[i]]=i;
    }
    FOR(i,1,n+1)FOR(j,1,i){
        if(pos[i]<pos[j]) ni[0][i][j]=1;
        else ni[1][i][j]=1;
    }
    FOR(i,1,n+1)FOR(j,1,n+1){
        pre[0][i][j]=pre[0][i-1][j]+pre[0][i][j-1]-pre[0][i-1][j-1]+ni[0][i][j];
        pre[1][i][j]=pre[1][i-1][j]+pre[1][i][j-1]-pre[1][i-1][j-1]+ni[1][i][j];
        //cout<<"pre["<<i<<"]["<<j<<"]="<<pre[i][j]<<endl;
    }
    dp[1]=0;
    FOR(i,2,n+1){
        dp[i]=pre[1][i][i];
        FOR(j,1,i){
            int tmp=pre[0][i][j]-pre[0][j][j],tmp2=pre[1][i][i]-pre[1][i][j]-pre[1][j][i]+pre[1][j][j];
            //cout<<"i="<<i<<" j="<<j<<" tmp="<<tmp<<" tmp2="<<tmp2<<endl;
            dp[i]=min(dp[i],tmp+tmp2+dp[j]);
        }
        //cout<<"dp["<<i<<"]="<<dp[i]<<endl;
    }
    cout<<dp[n]<<endl;
}

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