Submission #1102324

#	Time	Username	Problem	Language	Result	Execution time	Memory
1102324		vjudge1	Swap Swap Sort (CCO21_day1problem1)	C++17	25 / 25	1344 ms	169512 KiB

Main

#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define el cout << '\n'
#define f1(i,n) for(int i=1;i<=n;i++)
#define __file_name ""
using namespace std;
const ll maxn = 1e6+5, inf=1e18;

struct FenwickTree{
    int n;
    vector<long long> bit;
    FenwickTree(){}
    FenwickTree(int n): n(n), bit(n+1, 0LL){}
    void update(int idx, long long v){
        if(idx <= 0) return;
        for(;idx<=n;idx+=(idx&-idx)) bit[idx]+=v;
    }
    long long getSum(int idx){
        if(idx <= 0) return 0;
        long long res = 0;
        for(;idx;idx-=idx&-idx) res += bit[idx];
        return res;
    }
};

int n, k, q, a[maxn], p[maxn], res[maxn];
vector<int> pos[maxn];
vector<pair<int,int>> qu[maxn];
unordered_map<int, ll> mp[maxn];
FenwickTree bit;
ll ans;

ll count_inv(int x, int y){
    if(mp[x].find(y) != mp[x].end()) return mp[x][y];
    ll res = 0;
    int i = 0;
    for(int j=0;j<pos[y].size();j++){
        while(i < pos[x].size() && pos[x][i] < pos[y][j]) i++;
        res += i;
    }
    mp[x][y] = res;
    return res;
}

int main(){
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);

    if(fopen(__file_name ".inp", "r")){
        freopen(__file_name ".inp","r",stdin);
        freopen(__file_name ".out","w",stdout);
    }
    // code here
    cin >> n >> k >> q;
    bit = FenwickTree(k);
    f1(i,n) {
        cin >> a[i];
        ans += bit.getSum(k) - bit.getSum(a[i]);
        bit.update(a[i], 1);
        pos[a[i]].push_back(i);
        p[i] = i;
        // pp[i] = i;
    }
    // cout << ans << endl;
    // qu[i] = {j, idx} -> number of elements j that is before i
    f1(i,q){
        int j; cin >> j;
        // count(x, y): number of elements x that is before y
        // answer += -pos[p[j]].size()*pos[p[j+1]].size() + 2*count_inv(p[j+1], p[j])
        // or answer += pos[p[j]].size()*pos[p[j+1]].size() - 2*count_inv(p[j], p[j+1])
        // answer += count_inv(p[j], p[j+1]) - count_inv(p[j+1], p[j])
        if(p[j] < p[j+1]){
            ans += -1LL*pos[p[j]].size()*pos[p[j+1]].size() + 2*count_inv(p[j], p[j+1]);
        }else{
            ans += +1LL * pos[p[j]].size()*pos[p[j+1]].size() - 2*count_inv(p[j+1], p[j]);
        }
        swap(p[j], p[j+1]);
        cout << ans;el;
    }
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'long long int count_inv(int, int)':
Main.cpp:40:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   40 |     for(int j=0;j<pos[y].size();j++){
      |                 ~^~~~~~~~~~~~~~
Main.cpp:41:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   41 |         while(i < pos[x].size() && pos[x][i] < pos[y][j]) i++;
      |               ~~^~~~~~~~~~~~~~~
Main.cpp: In function 'int main()':
Main.cpp:52:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   52 |         freopen(__file_name ".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:53:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   53 |         freopen(__file_name ".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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