Submission #854223

#	Time	Username	Problem	Language	Result	Execution time	Memory
854223		PagodePaiva	Swap Swap Sort (CCO21_day1problem1)	C++17	25 / 25	3507 ms	87232 KiB

Main

#include<bits/stdc++.h>
#define N 100010
#define int long long

using namespace std;

int n, k, q;

struct BIT{
    int node[N];

    void add(int pos, int x){
        for(int i = pos;i <= k;i += (i & -i)){
            node[i] += x;
        }
    }

    int query(int pos){
        int s = 0;

        for(int i = pos;i > 0;i -= (i & -i)){
            s += node[i];
        }

        return s;
    }
} dp;

map <pair <int, int>, int> m;
vector <int> mark[N];

int32_t main(){
    cin >> n >> k >> q;

    vector <int> v;

    int ig = 0;

    for(int i = 0;i < n;i++){
        int x;
        cin >> x;
        v.push_back(x); 
        mark[x].push_back(i);
    }

    for(int i = 1;i <= k;i++){
        sort(mark[i].begin(), mark[i].end());
        ig += (mark[i].size()*(mark[i].size() -1))/2;
    }

    int res = 0;

    for(int i = 0;i < n;i++){
        res += dp.query(v[i]-1);
        dp.add(v[i], 1);
    }

    res = n*(n-1)/2 - res;
    res -= ig;

    // cout << res << '\n';

    vector <int> pos;

    for(int i = 1;i <= n;i++){
        pos.push_back(i);
    }

    for(int i = 0;i < q;i++){
        int x;
        cin >> x;

        int a = pos[x-1], b = pos[x];
        swap(pos[x-1], pos[x]);

        if(m.find({a, b}) != m.end()){
            res += m[{a, b}];
            cout << res << '\n';
            continue;
        }

        bool swp = false;
        if(mark[a].size() > mark[b].size()){swap(a, b); swp = true;}

        int aux = 0;

        for(auto x : mark[a]){
            auto it = upper_bound(mark[b].begin(), mark[b].end(), x);
            aux += it - mark[b].begin();
        }

        if(!swp){
            res += -2*aux + mark[a].size()*mark[b].size();
            m[{a, b}] = -2*aux + mark[a].size()*mark[b].size();
        }

        else{
            res -= mark[a].size()*mark[b].size() - 2*aux;
            m[{b, a}] = -(mark[a].size()*mark[b].size() - 2*aux);
        }

        cout << res << "\n";

    }
}  

• Subtask 1: 3 / 3
• Subtask 2: 3 / 3
• Subtask 3: 5 / 5
• Subtask 4: 14 / 14