Submission #420355

#	Time	Username	Problem	Language	Result	Execution time	Memory
420355		Aldas25	Sorting (IOI15_sorting)	C++14	100 / 100	535 ms	24320 KiB

sorting

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

using namespace std;

#define FAST_IO ios_base::sync_with_stdio(0); cin.tie(nullptr)
#define FOR(i, a, b) for (int i = (a); i <= (b); i++)
#define REP(n) FOR(O, 1, (n))
#define f first
#define s second
#define pb push_back
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<pii> vii;
typedef vector<ll> vl;

const int MAXN = 200100;

int ids[MAXN];
int vals[MAXN];
int whereId[MAXN], whereVal[MAXN];
vii valSwaps;

int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
    bool isSorted = true;
    FOR(i, 0, N-1) if (S[i] != i) isSorted = false;
    if (isSorted) return 0;



    int le = 1, ri = M;
    while (le < ri) {
        int mid = (le+ri)/2;

        FOR(i, 0, mid-1) P[i] = Q[i] = 0;

        FOR(i, 0, N-1) {
            ids[i] = i;
            vals[i] = S[i];
            whereId[i] = i;
            whereVal[S[i]] = i;
        }

        FOR(i, 0, mid-1) {
            int a = X[i], b = Y[i];
            int id1 = whereId[a], id2 = whereId[b];
            swap(whereId[a], whereId[b]);
            swap(ids[id1], ids[id2]);
        }

       // cout << " after enemy swaps:";
       // FOR(i, 0, N-1) cout << " " << ids[i];
       // cout << endl;

        valSwaps.clear();
        FOR(i,0,N-2) {
            int val1 = vals[i], val2 = ids[i];
            if (val1 == val2) continue;
            int id1 = i, id2 = whereVal[val2];
            swap(vals[id1], vals[id2]);
            swap(whereVal[val1], whereVal[val2]);
            valSwaps.pb({val1, val2});
        }

       // cout << " valSwaps:" << endl;
       // for (auto pp : valSwaps) cout << "    " << pp.f << ", " << pp.s << endl;

        FOR(i, 0, N-1) {
            ids[i] = i;
            vals[i] = S[i];
            whereId[i] = i;
            whereVal[S[i]] = i;
        }

        FOR(i, 0, (int)valSwaps.size()-1) {
            int a = X[i], b = Y[i];
            int id1 = whereId[a], id2 = whereId[b];
            swap(whereId[a], whereId[b]);
            swap(ids[id1], ids[id2]);

            a = valSwaps[i].f, b = valSwaps[i].s;
            id1 = whereVal[a], id2 = whereVal[b];
            swap(vals[id1], vals[id2]);
            swap(whereVal[a], whereVal[b]);
            P[i] = ids[id1];
            Q[i] = ids[id2];
        }

        if ((int)valSwaps.size() <= mid) ri = mid;
        else le = mid+1;
    }

    FOR(i, 0, le-1) P[i] = Q[i] = 0;

    FOR(i, 0, N-1) {
        ids[i] = i;
        vals[i] = S[i];
        whereId[i] = i;
        whereVal[S[i]] = i;
    }

    FOR(i, 0, le-1) {
        int a = X[i], b = Y[i];
        int id1 = whereId[a], id2 = whereId[b];
        swap(whereId[a], whereId[b]);
        swap(ids[id1], ids[id2]);
    }

   // cout << " after enemy swaps:";
   // FOR(i, 0, N-1) cout << " " << ids[i];
   // cout << endl;

    valSwaps.clear();
    FOR(i,0,N-2) {
        int val1 = vals[i], val2 = ids[i];
        if (val1 == val2) continue;
        int id1 = i, id2 = whereVal[val2];
        swap(vals[id1], vals[id2]);
        swap(whereVal[val1], whereVal[val2]);
        valSwaps.pb({val1, val2});
    }

   // cout << " valSwaps:" << endl;
   // for (auto pp : valSwaps) cout << "    " << pp.f << ", " << pp.s << endl;

    FOR(i, 0, N-1) {
        ids[i] = i;
        vals[i] = S[i];
        whereId[i] = i;
        whereVal[S[i]] = i;
    }

    FOR(i, 0, (int)valSwaps.size()-1) {
        int a = X[i], b = Y[i];
        int id1 = whereId[a], id2 = whereId[b];
        swap(whereId[a], whereId[b]);
        swap(ids[id1], ids[id2]);

        a = valSwaps[i].f, b = valSwaps[i].s;
        id1 = whereVal[a], id2 = whereVal[b];
        swap(vals[id1], vals[id2]);
        swap(whereVal[a], whereVal[b]);
        P[i] = ids[id1];
        Q[i] = ids[id2];
    }

    return le;
}

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