# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
299341 | Hideo | Sorting (IOI15_sorting) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
//#include "sorting.h"
#include "grader.cpp"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define all(s) s.begin(), s.end()
#define pb push_back
#define fr first
#define sc second
#define vi vector < int >
#define pi pair < int, int >
const int MN = 3e5 + 7;
vector < pi > sw, out;
int a[MN], b[MN], r[MN];
int x[MN], y[MN];
int n, m;
bool check (int k){
for (int i = 0; i < n; i++)
a[i] = b[i];
for (int i = 0; i < k; i++)
swap(a[x[i]], a[y[i]]);
queue < pi > q;
for (int i = 0; i < n; i++)
r[a[i]] = i;
for (int i = 0; i < n; i++)
if (a[a[i]] == i)
q.push({i, a[i]});
int l = 0, cnt = 0;
vector < pi > kek;
while (l < n){
while (!q.empty()){
int v = q.front().fr, u = q.front().sc;
q.pop();
if (r[v] == v)
continue;
kek.pb({v, u});
swap(a[v], a[u]);
swap(r[a[v]], r[a[u]]);
cnt++;
}
if (r[l] != l){
int v = l, u = r[l];
kek.pb({v, a[v]});
swap(a[v], a[u]);
swap(r[a[v]], r[a[u]]);
if (a[a[u]] == u)
q.push({u, a[u]});
cnt++;
}
l++;
}
if (cnt <= k)
sw = kek;
return cnt <= k;
}
void simulate (int k){
while (sw.size() != k)
sw.pb({0, 0});
for (int i = 0; i < n; i++){
a[i] = b[i];
r[a[i]] = i;
}
for (int i = 0; i < k; i++){
swap(a[x[i]], a[y[i]]);
swap(r[a[x[i]]], r[a[y[i]]]);
int v = r[sw[i].fr], u = r[sw[i].sc];
out.pb({v, u});
swap(a[v], a[u]);
swap(r[a[v]], r[a[u]]);
}
}
int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
n = N; m = M;
bool sorted = true;
for (int i = 0; i < n; i++){
b[i] = S[i];
if (b[i] != i)
sorted = false;
}
if (sorted)
return 0;
for (int i = 0; i < m; i++){
x[i] = X[i];
y[i] = Y[i];
}
int lf = 0, rg = M;
while (lf + 1 < rg){
int mid = (lf + rg) >> 1;
if (check(mid))
rg = mid;
else
lf = mid;
}
for (int i = max(1, rg - 10); i < rg; i++){
if (check(i))
rg = i;
}
simulate(rg);
for (int i = 0; i < out.size(); i++){
P[i] = out[i].fr;
Q[i] = out[i].sc;
}
return rg;
}