Submission #712902

#	Time	Username	Problem	Language	Result	Execution time	Memory
712902		Nhoksocqt1	Sorting (IOI15_sorting)	C++17	74 / 100	1098 ms	209788 KiB

sorting

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

#define inf 0x3f3f3f3f
#define sz(x) int((x).size())
#define fi first
#define se second
#define round asfhuqfuqwhuqwer
typedef long long ll;
typedef pair<int, int> ii;

template<class X, class Y>
	inline bool maximize(X &x, const Y &y) {return (x < y ? x = y, 1 : 0);}
template<class X, class Y>
	inline bool minimize(X &x, const Y &y) {return (x > y ? x = y, 1 : 0);}

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int Random(int l, int r) {
    return uniform_int_distribution<int>(l, r)(rng);
}

const int MAXN = 200005;

ii round[3 * MAXN];
int val[MAXN], P[6 * MAXN][21], Pn[6 * MAXN][21], lastOf[MAXN];
int lastIdx[MAXN], pos[MAXN], tmp[MAXN], nArr, numRound;

#ifdef Nhoksocqt1

int findSwapPairs(int _N, int _S[], int _M, int _X[], int _Y[], int _P[], int _Q[]);
int _S[MAXN], _X[MAXN], _Y[MAXN], _P[MAXN], _Q[MAXN];

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

    freopen("SORTING.inp", "r", stdin);
    freopen("SORTING.out", "w", stdout);

    int _N, _M;
    cin >> _N;
    for (int i = 0; i < _N; ++i)
        cin >> _S[i];

    //for (int i = 0; i < _N; ++i) _S[i] = i; shuffle(_S, _S + _N, rng); for (int i = 0; i < _N; ++i) cout << _S[i] << " \n"[i + 1 == _N];

    cin >> _M;
    for (int i = 0; i < _M; ++i) {
        cin >> _X[i];
        //_X[i] = Random(0, _N - 1); cout << _X[i] << " \n"[i + 1 == _M];
    }

    for (int i = 0; i < _M; ++i) {
        cin >> _Y[i];
        //_Y[i] = Random(0, _N - 1); cout << _Y[i] << " \n"[i + 1 == _M];
    }

    int ans = findSwapPairs(_N, _S, _M, _X, _Y, _P, _Q);
    cout << ans << '\n';
    for (int it = 0; it < ans; ++it)
        cout << _P[it] << ' ' << _Q[it] << '\n';

    return 0;
}

#endif // Nhoksocqt1

inline int getID(int x) {
    return (x > numRound) ? round[x - numRound].fi : round[x].se;
}

bool check(int nr, int _P[], int _Q[]) {
    for (int i = 1; i <= nArr; ++i) {
        tmp[i] = val[i];
        pos[val[i]] = i;
    }

    swap(pos[tmp[round[1].fi]], pos[tmp[round[1].se]]);
    swap(tmp[round[1].fi], tmp[round[1].se]);

    int cntNow(1);
    for (int i = 1; i <= nArr; ++i) {
        int from(lastOf[i]);
        for (int j = 20; j >= 0; --j) {
            int now(Pn[from][j]);
            if(now <= numRound && now > nr || now > numRound && now - numRound > nr)
                from = now;
        }

        if(from <= numRound && from > nr || from > numRound && from - numRound > nr)
            from = Pn[from][0];

        //cout << ',' << from << ' ';
        for (int j = 20; j >= 0; --j) {
            int now(P[from][j]);
            if(!now)
                continue;

            //cout << now << ' ' << cntNow << '.';
            if(now <= numRound && now > cntNow || now > numRound && now - numRound > cntNow)
                from = now;
        }

        //cout << nr << ' ' << i << ' ' << tmp[getID(from)] << ' ' << lastOf[i] << ' ' << from << ' ' << getID(from) << '\n';
        bool checkCond = (from <= numRound && from > cntNow || from > numRound && from - numRound > cntNow);
        if(checkCond && tmp[getID(from)] == i || !checkCond && tmp[i] == i)
            continue;

        if(cntNow > nr)
            return false;

        int x(pos[i]), y;
        if(checkCond) {
            x = pos[i], y = getID(from);
        } else {
            x = pos[i], y = i;
        }

        _P[cntNow - 1] = x - 1, _Q[cntNow - 1] = y - 1;
        swap(pos[tmp[x]], pos[tmp[y]]);
        swap(tmp[x], tmp[y]);

        //cout << '.' << x << ' ' << y << '\n';
        if(++cntNow <= nr) {
            swap(pos[tmp[round[cntNow].fi]], pos[tmp[round[cntNow].se]]);
            swap(tmp[round[cntNow].fi], tmp[round[cntNow].se]);
        }
    }

    for (int i = cntNow - 1; i < nr; ++i)
        _P[i] = _Q[i] = 0;

    for (int i = cntNow + 1; i <= nr; ++i)
        swap(tmp[round[i].fi], tmp[round[i].se]);

    /*cout << nr << ": ";
    for (int i = 1; i <= nArr; ++i)
        cout << tmp[i] << " \n"[i == nArr];*/

    return true;
}

int findSwapPairs(int _N, int _S[], int _M, int _X[], int _Y[], int _P[], int _Q[]) {
    nArr = _N, numRound = _M;

    bool check0(1);
    for (int i = 1; i <= nArr; ++i) {
        val[i] = _S[i - 1] + 1;
        check0 &= (val[i] == i);
    }

    if(check0)
        return 0;

    for (int i = 1; i <= numRound; ++i) {
        round[i] = {_X[i - 1] + 1, _Y[i - 1] + 1};
        P[i][0] = lastIdx[round[i].se];
        P[i + numRound][0] = lastIdx[round[i].fi];
        lastIdx[round[i].fi] = i;
        lastIdx[round[i].se] = i + numRound;
    }

    for (int i = 1; i <= nArr; ++i)
        lastIdx[i] = 0;

    for (int i = 1; i <= numRound; ++i) {
        Pn[i][0] = lastIdx[round[i].fi];
        Pn[i + numRound][0] = lastIdx[round[i].se];
        lastIdx[round[i].fi] = i;
        lastIdx[round[i].se] = i + numRound;
        lastOf[round[i].fi] = i;
        lastOf[round[i].se] = i + numRound;
    }

    for (int j = 1; j <= 20; ++j) {
        for (int i = 1; i <= 2 * numRound; ++i) {
            P[i][j] = P[P[i][j - 1]][j - 1];
            Pn[i][j] = Pn[Pn[i][j - 1]][j - 1];
        }
    }

    int l(1), r(numRound - 1), answer(r + 1);
    while(l <= r) {
        int mid = (l + r) >> 1;
        if(check(mid, _P, _Q)) {
            answer = mid;
            r = mid - 1;
        } else {
            l = mid + 1;
        }
    }

    check(answer, _P, _Q);
    return answer;
}

Compilation message (stderr)

sorting.cpp: In function 'bool check(int, int*, int*)':
sorting.cpp:86:32: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   86 |             if(now <= numRound && now > nr || now > numRound && now - numRound > nr)
      |                ~~~~~~~~~~~~~~~~^~~~~~~~~~~
sorting.cpp:90:29: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   90 |         if(from <= numRound && from > nr || from > numRound && from - numRound > nr)
      |            ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~
sorting.cpp:100:32: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  100 |             if(now <= numRound && now > cntNow || now > numRound && now - numRound > cntNow)
      |                ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~
sorting.cpp:105:44: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  105 |         bool checkCond = (from <= numRound && from > cntNow || from > numRound && from - numRound > cntNow);
      |                           ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~
sorting.cpp:106:22: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  106 |         if(checkCond && tmp[getID(from)] == i || !checkCond && tmp[i] == i)
      |            ~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 12 / 12
• Subtask 3: 16 / 16
• Subtask 4: 18 / 18
• Subtask 5: 20 / 20
• Subtask 6: 0 / 26