# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
314642 | amunduzbaev | Sorting (IOI15_sorting) | C++14 | 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 "grader.cpp"
#include "sorting.h"
#include <bits/stdc++.h>
using namespace std;
#define pb(a) push_back(a)
const int N=2*1e5+5;
int n, s[N], x[N], y[N];
vector<pair<int,int>>ans;
bool check(int m){
int a[N], pos[N];
for(int i=0;i<n;i++) a[i]=s[i];
for(int i=0;i<m;i++) swap(a[x[i]], a[y[i]]);
for(int i=0;i<n;i++) pos[a[i]]=i;
vector<int> sx, sy;
for(int i=0;i<n;i++){
if(pos[i]!=i){
int j=pos[i];
sx.pb(a[i]);
sy.pb(a[j]);
pos[a[i]]=j;
swap(a[i],a[j]);
}
}
if(sx.size()>m) return false;
ans.clear();
for(int i=0;i<n;i++) a[i]=s[i], pos[a[i]]=i;
for(int i=0;i<sx.size();i++){
ans.pb({pos[sx[i]], pos[sy[i]]});
int i1=pos[sx[i]],j1=pos[sy[i]];
swap ( a[y[i]] ,a[y[i]] );
swap ( a[i1], a[j1] );
swap ( pos[a[x1]], pos[a[y1]] );
swap ( pos[a[i1]], pos[a[j1]] );
}
for(int i=sx.size(); i<m; i++)
ans.pb({0,0});
return true;
}
int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
n=N;
for(int i=0;i<n;i++) s[i]=S[i];
for(int i=0;i<M;i++) x[i]=X[i], y[i]=Y[i];
int l=0,r=M;
while(l<r){
int md=(l+r)/2;
if(check(md)) r=md;
else l=md+1;
}
for(int i=0;i<ans.size();i++){
P[i]=ans[i].first;
Q[i]=ans[i].second;
}
return l;
}