Submission #534849

#	Time	Username	Problem	Language	Result	Execution time	Memory
534849		Paul_Liao_1457	Group Photo (JOI21_ho_t3)	C++14	0 / 100	1 ms	316 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 INF (ll)(1e9)
#define pb push_back
#define AC ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);

using namespace std;

int bit[5005],a[5005],b[5005],n,pos[5005];

void add(int x){
    for(int i=x;i>0;i-=i&(-i)) bit[i]++;
}

int ask(int x){
    int r=0;
    for(int i=x;i<=n;i+=i&(-i)){
        r+=bit[i];
    }
    return r;
}

int cnt(){
    int ans=0;
    FOR(i,1,n+1) bit[i]=0;
    FOR(i,1,n+1){
        ans+=ask(b[i]);
        add(b[i]);
    }
    return ans;
}

signed main(){
    AC;
    int res;
    cin>>n;
    vector<int> v;
    FOR(i,1,n+1){
        v.pb(i);
        cin>>a[i]; pos[a[i]]=i;
    }
    FOR(i,1,n+1){
        b[i]=a[i];
    }
    res=cnt();
    do{
        FOR(i,0,n) b[pos[v[i]]]=i+1;
        res=min(res,cnt());
    }while(next_permutation(v.begin(),v.end()));
    cout<<res<<endl;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 7
• Subtask 3: 0 / 32
• Subtask 4: 0 / 20
• Subtask 5: 0 / 36