Submission #583483

#	Time	Username	Problem	Language	Result	Execution time	Memory
583483		AngusWong	Group Photo (JOI21_ho_t3)	C++17	44 / 100	5012 ms	320 KiB

Main

#include <bits/stdc++.h>
using namespace std;

int n, a[5001], p, pos[5001], t, dp[5001], bit[5001];
vector<int> v;

void upd(int x){
    for (int i=x; i<=n; i+=(i&(-i))) bit[i]++;
}

int qry(int x){
    int ans=0;
    for (int i=x; i; i-=(i&(-i))) ans+=bit[i];
    return ans;
}

int main() {
    cin >> n;
    for (int i=1; i<=n; i++) cin >> a[i];
    for (int i=1; i<=n; i++){
        dp[i]=2e9;
        for (int j=1; j<=i; j++){
            p=1;
            v.clear();
            v.push_back(-1);
            for (int k=1; k<=n; k++) bit[k]=0;
            for (int k=i; k>=j; k--) pos[k]=p++;
            for (int k=1; k<=n; k++){
                if (a[k]>i) pos[a[k]]=p++;
                if (a[k]>=j) v.push_back(a[k]);
            }
            t=0;
            for (int k=1; k<v.size(); k++){
                t+=qry(n)-qry(pos[v[k]]);
                upd(pos[v[k]]);
            }
            dp[i]=min(dp[i], dp[j-1]+t);
        }
    }
    cout << dp[n] << "\n";
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:33:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   33 |             for (int k=1; k<v.size(); k++){
      |                           ~^~~~~~~~~

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