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Submission #316558

# Submission time Handle Problem Language Result Execution time Memory
316558 2020-10-26T16:26:53 Z mohamedsobhi777 Sorting (IOI15_sorting) C++14
36 / 100
 2 ms 640 KB 
#include <bits/stdc++.h>
#include "sorting.h"

using namespace std;
const int _N = 2e5;

int n, m;
int s[_N], _s[_N];
int x[_N], y[_N];
int nxt[_N];
int t;
int viz[_N];
int Nxt[_N];
int cyc = 0;
int pos[_N];
int rep[_N];

int cycles()
{
        ++t;
        int ret = 0;
        for (int i = 0; i < n; ++i)
        {
                int cnt = 1;
                int cur = Nxt[i];
                if (viz[i] == t)
                        continue;
                ++ret;
                while (cur != i)
                {
                        viz[cur] = t;
                        cur = Nxt[cur];
                        ++cnt;
                }
                viz[cur] = t;
        }
        return ret;
}
vector<pair<int, int>> ans, ans2;

void solve(int X)
{
        map<int, int> vis;
        for (int i = 0; i < n; ++i)
        {
                if (vis[i])
                        continue;
                int cur = Nxt[i];
                while (cur != i)
                {
                        ++vis[cur];
                        ans.push_back({i, cur});
                        cur = Nxt[cur];
                }
                ++vis[cur];
        }
        while (ans.size() < X)
                ans.push_back({0, 0});
        ans2.resize(X);

        for (int i = 0; i < n; ++i)
                pos[s[i]] = i;

        for (int i = 0; i < X; ++i)
        {
                int x1 = pos[_s[x[i]]];
                int x2 = pos[_s[y[i]]];
                swap(rep[x1], rep[x2]);
                ans2[i] = {rep[ans[i].first], rep[ans[i].second]};
                swap(_s[x[i]], _s[y[i]]);
        }
}

bool can(int mid)
{
        int nxt[_N];
        for (int i = 0; i < n; ++i)
                nxt[i] = s[i];
        for (int j = 0; j <= mid; ++j)
                swap(nxt[x[j]], nxt[y[j]]);
        ++t;
        int ret = 0;
        for (int i = 0; i < n; ++i)
        {
                int cnt = 1;
                int cur = nxt[i];
                if (viz[i] == t)
                        continue;
                ++ret;
                while (cur != i)
                {
                        viz[cur] = t;
                        cur = nxt[cur];
                        ++cnt;
                }
                viz[cur] = t;
        }
        return n - ret <= mid;
}

int binary_sr4()
{
        int ret = m;
        int lo = 0, hi = m;
        while (lo <= hi)
        {
                int mid = (lo + hi) >> 1;
                if (can(mid))
                        hi = mid - 1, ret = mid;
                else
                        lo = mid + 1;
        }
        return ret;
}

int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[])
{
        n = N;
        m = M;
        for (int i = 0; i < N; ++i)
        {
                Nxt[i] = S[i];
                s[i] = S[i];
                _s[i] = S[i];
                rep[i] = i;
        }
        cyc = cycles();
        if (n - cyc == 0)
                return 0;
        int opt = binary_sr4();
        for (int i = 0; i < M; ++i)
        {
                x[i] = X[i];
                y[i] = Y[i];
                swap(s[X[i]], s[Y[i]]);
                swap(rep[X[i]], rep[Y[i]]);
                swap(Nxt[X[i]], Nxt[Y[i]]);
                if (abs(i - opt) <= 10 && n - cycles() <= i + 1)
                {
                        solve(i + 1);
                        for (int j = 0; j <= i; ++j)
                        {
                                P[j] = ans2[j].first;
                                Q[j] = ans2[j].second;
                        }
                        return ++i;
                }
        }
        return 0;
}

Compilation message

sorting.cpp: In function 'void solve(int)':
sorting.cpp:57:27: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   57 |         while (ans.size() < X)
      |                ~~~~~~~~~~~^~~
sorting.cpp: In function 'bool can(int)':
sorting.cpp:76:19: warning: declaration of 'nxt' shadows a global declaration [-Wshadow]
   76 |         int nxt[_N];
      |                   ^
sorting.cpp:10:5: note: shadowed declaration is here
   10 | int nxt[_N];
      |     ^~~

Subtask #1
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Correct 0 ms 384 KB Output is correct
6 Correct 0 ms 384 KB Output is correct
7 Correct 1 ms 384 KB Output is correct

Subtask #2
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Correct 0 ms 384 KB Output is correct
6 Correct 0 ms 384 KB Output is correct
7 Correct 1 ms 384 KB Output is correct
8 Correct 1 ms 384 KB Output is correct
9 Correct 1 ms 384 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 1 ms 384 KB Output is correct
12 Correct 0 ms 384 KB Output is correct

Subtask #3
16.0 / 16.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 1 ms 512 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Correct 1 ms 384 KB Output is correct
6 Correct 1 ms 384 KB Output is correct

Subtask #4
0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Correct 0 ms 384 KB Output is correct
6 Correct 0 ms 384 KB Output is correct
7 Correct 1 ms 384 KB Output is correct
8 Correct 1 ms 384 KB Output is correct
9 Correct 1 ms 384 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 1 ms 384 KB Output is correct
12 Correct 0 ms 384 KB Output is correct
13 Correct 0 ms 384 KB Output is correct
14 Correct 0 ms 384 KB Output is correct
15 Correct 1 ms 512 KB Output is correct
16 Correct 1 ms 384 KB Output is correct
17 Correct 1 ms 384 KB Output is correct
18 Correct 1 ms 384 KB Output is correct
19 Correct 0 ms 384 KB Output is correct
20 Correct 1 ms 384 KB Output is correct
21 Correct 1 ms 512 KB Output is correct
22 Correct 1 ms 512 KB Output is correct
23 Correct 2 ms 512 KB Output is correct
24 Incorrect 1 ms 640 KB Output isn't correct
25 Halted 0 ms 0 KB -

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 640 KB Output is correct
2 Correct 2 ms 640 KB Output is correct
3 Correct 2 ms 640 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Incorrect 1 ms 512 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #6
0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 640 KB Output is correct
2 Correct 2 ms 640 KB Output is correct
3 Correct 2 ms 640 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Incorrect 1 ms 512 KB Output isn't correct
6 Halted 0 ms 0 KB -