Submission #1239886

#	Time	Username	Problem	Language	Result	Execution time	Memory
1239886		Geforgs	Group Photo (JOI21_ho_t3)	C++20	100 / 100	61 ms	596 KiB

Main

#include <iostream>
#include <iomanip>
#include <vector>
#include <cmath>
#include <algorithm>
#include <set>
#include <queue>
#include <map>
#include <unordered_map>
#include <stack>
#include <bitset>
#include <string>
#include <cstring>
#include <iterator>
#include <random>
#define ll long long
#define ld long double
#define inf (ll)(2*1e18)
#define sort(a) sort(a.begin(), a.end())
#define reverse(a) reverse(a.begin(), a.end())
#define pb push_back
//#define endl "\n"
using namespace std;

void solve(){
    ll n, i, j, last;
    cin>>n;
    vector<ll> a(n+1);
    vector<ll> b(n+1);
    vector<ll> dp(n+1);
    vector<ll> d(n+1);
    for(i=0;i<n;++i){
        cin>>a[i];
        b[a[i]] = i;
    }
    for(i=2;i<=n;++i){
        last = 0;
        for(j=b[i]+1;j<n;++j){
            if(a[j] < i) d[i-1]++, last++;
        }
        dp[i] = dp[i-1] + last;
        for(j=i-2;j>=0;--j){
            if(b[j+1] > b[i]){
                --last;
            }else{
                ++last;
            }
            d[j] += last;
            dp[i] = min(dp[i], dp[j] + d[j]);
        }
    }
    cout<<dp[n]<<endl;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    srand(time(nullptr));
    ll t=1;
//    cin>>t;
    for(;t>0;--t){
        solve();
    }
    return 0;
}

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