Submission #443699

#	Time	Username	Problem	Language	Result	Execution time	Memory
443699		zaneyu	Group Photo (JOI21_ho_t3)	C++14	100 / 100	594 ms	67584 KiB

Main

/*input
9
6 1 3 4 9 5 7 8 2
*/
#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef tree<int,null_type,less_equal<int>,rb_tree_tag,tree_order_statistics_node_update> indexed_set;
//order_of_key #of elements less than x
// find_by_order kth element
using ll=long long;
using ld=double;
using pii=pair<int,int>;
#define f first
#define s second
#define pb push_back
#define REP(i,n) for(int i=0;i<n;i++)
#define REP1(i,n) for(int i=1;i<=n;i++)
#define FILL(n,x) memset(n,x,sizeof(n))
#define ALL(_a) _a.begin(),_a.end()
#define sz(x) (int)x.size()
#define SORT_UNIQUE(c) (sort(c.begin(),c.end()),c.resize(distance(c.begin(),unique(c.begin(),c.end()))))
const ll INF64=1e18+1;
const int INF=0x3f3f3f3f;
const int MOD=1e9+9;
const ld PI=acos(-1);
const ld eps=1e-6;
#define lowb(x) x&(-x)
#define MNTO(x,y) x=min(x,(__typeof__(x))y)
#define MXTO(x,y) x=max(x,(__typeof__(x))y)
inline ll mult(ll a,ll b){
    if(a>=MOD) a%=MOD;
    if(b>=MOD) b%=MOD;
    return (a*b)%MOD;
}
inline ll mypow(ll a,ll b){
    if(b<=0) return 1;
    ll res=1LL;
    while(b){
        if(b&1) res=mult(res,a);
        a=mult(a,a);
        b>>=1;
    }
    return res;
}
const int maxn=5e3+5;
const int maxlg=__lg(maxn)+2;
int cnt[maxn][maxn];
int dp[maxn];
int pos[maxn],bit[maxn],pref[maxn];
inline void upd(int p){
    while(p<maxn){
        bit[p]++;
        p+=lowb(p);
    }
}
int query(int p){
    int ans=0;
    while(p){
        ans+=bit[p];
        p-=lowb(p);
    }
    return ans;
}
int32_t main(){
    ios::sync_with_stdio(false),cin.tie(0);
    int n;
    cin>>n;
    REP1(i,n){
        int x;
        cin>>x;
        pos[x]=i;
    }
    REP1(i,n){
        REP(j,maxn) bit[j]=0,pref[j]=0;
        REP1(j,i-1) pref[pos[j]]++;
        REP1(j,n) pref[j]+=pref[j-1];
        for(int j=i;j<=n;j++){
            cnt[i][j]=cnt[i][j-1];
            cnt[i][j]+=query(pos[j])+i-1-pref[pos[j]];
            upd(pos[j]);
        }
    }
    REP1(i,n){
        dp[i]=INF;
        REP1(j,i){
            MNTO(dp[i],dp[j-1]+cnt[j][i]);
        }
    }
    cout<<dp[n];
}  

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