Submission #1149703

#	Time	Username	Problem	Language	Result	Execution time	Memory
1149703		Lib	Sorting (IOI15_sorting)	C++20	100 / 100	88 ms	11616 KiB

sorting

#include <bits/stdc++.h>
#include "sorting.h"
 //stolen from steveonalex

using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
 
#define MASK(i) (1LL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()
#define block_of_code if(true)
 
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
ll gcd(ll a, ll b){return __gcd(a, b);}
ll lcm(ll a, ll b){return a / gcd(a, b) * b;}
 
ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ll mask){return __builtin_popcountll(mask);}
int ctz(ull mask){return __builtin_ctzll(mask);}
int logOf(ull mask){return 63 - __builtin_clzll(mask);}
 
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rngesus(ll l, ll r){return l + (ull) rng() % (r - l + 1);}
 
template <class T1, class T2>
    bool maximize(T1 &a, T2 b){
        if (a < b) {a = b; return true;}
        return false;
    }
 
template <class T1, class T2>
    bool minimize(T1 &a, T2 b){
        if (a > b) {a = b; return true;}
        return false;
    }
 
template <class T>
    void printArr(T container, string separator = " ", string finish = "\n", ostream &out = cout){
        for(auto item: container) out << item << separator;
        out << finish;
    }
 
template <class T>
    void remove_dup(vector<T> &a){
        sort(ALL(a));
        a.resize(unique(ALL(a)) - a.begin());
    }



int findSwapPairs(int n, int a[], int m, int x[], int y[], int p[], int q[]) {
    minimize(m, n);

    int L = 0, R = m;
    while(L < R){
        int mid = (L + R) >> 1;
        vector<int> perm(n);
        for(int i = 0; i < n; ++i) perm[i] = a[i];
        for(int i = 0; i < mid; ++i){
            swap(perm[x[i]], perm[y[i]]);
        }

        vector<bool> visited(n);
        int cnt = 0;
        for(int i = 0; i<n; ++i) if (!visited[i]) {
            int u = i;
            while(!visited[u]){
                visited[u] = true;
                if (!visited[perm[u]]) cnt++;
                u = perm[u];
            }
        }

        if (cnt <= mid) R = mid;
        else L = mid + 1;
    }

    vector<int> perm(n);
    for(int i = 0; i < n; ++i) perm[i] = a[i];
    for(int i = 0; i < R; ++i) swap(perm[x[i]], perm[y[i]]);

    vector<bool> visited(n);
    vector<pair<int,int>> swaps;
    for(int i = 0; i<n; ++i) if (!visited[i]) {
        int u = i;
        while(!visited[u]){
            visited[u] = true;
            if (!visited[perm[u]]) swaps.push_back({u, perm[u]});
            u = perm[u];
        }
    }

    reverse(ALL(swaps));
    vector<int> pos(n);
    for(int i = 0; i<n; ++i) perm[i] = a[i];
    for(int i = 0; i<n; ++i) pos[perm[i]] = i;
    for(int i = 0; i < R; ++i){
        int u = x[i], v = y[i];
        swap(perm[u], perm[v]);
        swap(pos[perm[u]], pos[perm[v]]);
        if (swaps.size()){
            u = pos[swaps.back().first], v = pos[swaps.back().second];
            swaps.pop_back();
        }
        else u = v = 0;
        swap(perm[u], perm[v]);
        swap(pos[perm[u]], pos[perm[v]]);

        p[i] = u, q[i] = v;
    }

    return R;
}

// int main(void){
//     ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

//     clock_t start = clock();

//     int n; cin >> n;
//     int a[n];
//     for(int i = 0; i<n; ++i) cin >> a[i];

//     int m; cin >> m;
//     int x[m], y[m];
//     for(int i = 0; i<m; ++i) cin >> x[i] >> y[i];

//     int p[m], q[m];
//     memset(p, -1, sizeof p); memset(q, -1, sizeof q);

//     int r = findSwapPairs(n, a, m, x, y, p, q);
//     cout << r << "\n";
//     for(int i = 0; i < r; ++i) {
//         swap(a[x[i]], a[y[i]]);
//         swap(a[p[i]], a[q[i]]);
//         cout << p[i] << " " << q[i] << "\n"; 
//     }

//     for(int i = 0; i < n; ++i) cout << a[i] << " "; cout << "\n";

//     cerr << "Time elapsed: " << clock() - start << " ms\n";

//     return 0;
// }

/*
5
4 3 2 1 0
6
0 1
1 2
2 3
3 4
0 1
1 2

*/

• Subtask 1: 8 / 8
• Subtask 2: 12 / 12
• Subtask 3: 16 / 16
• Subtask 4: 18 / 18
• Subtask 5: 20 / 20
• Subtask 6: 26 / 26