Submission #1091175

#	Time	Username	Problem	Language	Result	Execution time	Memory
1091175		yogesh_sane	Group Photo (JOI21_ho_t3)	C++17	64 / 100	5064 ms	600 KiB

Main

#include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
#include <queue>
using namespace std;
 
int n;
int const inf = 1e9;
vector<int>a, idx;
vector<int>cost;
int total_cost;
void calculate_cost(int val){
    vector<int>p(n+1);
    iota(p.begin(), p.end(), 0);
    reverse(p.begin()+1, p.begin()+val+1);
    for(int i = val; i >= 1; i--){
        int inv = 0;
        for(int j = i+1; j <= n; j++){
            if((p[i] < p[j] && idx[i] > idx[j]) ||
               (p[i] > p[j] && idx[i] < idx[j]))
               inv++;
        }
        cost.push_back(inv);
        total_cost += inv;
    }
}
 
int main(){
    cin >> n;
    a.resize(n+1);
    idx.resize(n+1);
    vector<int>dp(n+1, inf);
    for(int i = 1; i <= n; i++){
        cin >> a[i];
        idx[a[i]] = i;
    }
    dp[0] = 0;
    for(int i = 1; i <= n; i++){
        calculate_cost(i);
        for(int j = 1; j <= i; j++){
            dp[i] = min(dp[i], dp[j-1] + total_cost);
            total_cost -= cost.back();
            cost.pop_back();
        }
    }
    cout << dp[n] << '\n';
    return 0;
}

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