#include<bits/stdc++.h>
using namespace std;
bool odw[3001],bul;
int n;
pair<int,int>tab[3001];
int pol[3001],wst[3001];
vector<pair<int,int>>pary;
void split(int w){
int v=wst[w];
if(!odw[v]){
odw[v]=1;odw[w]=1;
pary.emplace_back(v,w);
//cout<<v<<" "<<w<<"\n";;
v=wst[v],w=pol[w];
while((v!=w)&&(!odw[v])&&(!odw[w])){
//cout<<v<<" "<<w<<"\n";;
pary.emplace_back(v,w);
odw[v]=1;odw[w]=1;
v=wst[v];w=pol[w];
}
}
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cin>>n;
for(int i=0;i<n;++i){
cin>>tab[i].first;
tab[i].second=i;
}
sort(tab,tab+n);
for(int i=0;i<n;++i){
pol[tab[i].second]=i;
wst[i]=tab[i].second;
}
for(int i=0;i<n;++i){
if(pol[i]!=i&&!odw[i]){
split(i);
bul=1;
}
}
if(!bul){
cout<<0<<"\n";
return 0;
}
bul=0;
for(int i=0;i<(int)pary.size();++i){
swap(pol[pary[i].first],pol[pary[i].second]);
}
for(int i=0;i<n;++i){
if(pol[i]!=i)bul=1;
}
if(!bul){
cout<<1<<"\n";
cout<<pary.size()*2<<"\n";
for(int i=0;i<(int)pary.size();++i){
cout<<pary[i].first+1<<" ";
}
for(int i=pary.size()-1;i>=0;--i){
cout<<pary[i].second+1<<" ";
}
}
else {
cout<<2<<"\n";
cout<<pary.size()*2<<"\n";
for(int i=0;i<(int)pary.size();++i){
cout<<pary[i].first+1<<" ";
}
for(int i=pary.size()-1;i>=0;--i){
cout<<pary[i].second+1<<" ";
}
cout<<"\n";
pary.clear();
for(int i=0;i<n;++i)odw[i]=0;
for(int i=0;i<n;++i){
if(pol[i]!=i&&!odw[i]){
pary.emplace_back(i,pol[i]);
odw[i]=1;odw[pol[i]]=1;
}
}
cout<<pary.size()*2<<"\n";
for(int i=0;i<(int)pary.size();++i){
cout<<pary[i].first+1<<" ";
}
for(int i=pary.size()-1;i>=0;--i){
cout<<pary[i].second+1<<" ";
}
}
}
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 | #include<bits/stdc++.h> using namespace std; bool odw[3001],bul; int n; pair<int,int>tab[3001]; int pol[3001],wst[3001]; vector<pair<int,int>>pary; void split(int w){ int v=wst[w]; if(!odw[v]){ odw[v]=1;odw[w]=1; pary.emplace_back(v,w); //cout<<v<<" "<<w<<"\n";; v=wst[v],w=pol[w]; while((v!=w)&&(!odw[v])&&(!odw[w])){ //cout<<v<<" "<<w<<"\n";; pary.emplace_back(v,w); odw[v]=1;odw[w]=1; v=wst[v];w=pol[w]; } } } int main(){ ios_base::sync_with_stdio(0); cin.tie(0); cin>>n; for(int i=0;i<n;++i){ cin>>tab[i].first; tab[i].second=i; } sort(tab,tab+n); for(int i=0;i<n;++i){ pol[tab[i].second]=i; wst[i]=tab[i].second; } for(int i=0;i<n;++i){ if(pol[i]!=i&&!odw[i]){ split(i); bul=1; } } if(!bul){ cout<<0<<"\n"; return 0; } bul=0; for(int i=0;i<(int)pary.size();++i){ swap(pol[pary[i].first],pol[pary[i].second]); } for(int i=0;i<n;++i){ if(pol[i]!=i)bul=1; } if(!bul){ cout<<1<<"\n"; cout<<pary.size()*2<<"\n"; for(int i=0;i<(int)pary.size();++i){ cout<<pary[i].first+1<<" "; } for(int i=pary.size()-1;i>=0;--i){ cout<<pary[i].second+1<<" "; } } else { cout<<2<<"\n"; cout<<pary.size()*2<<"\n"; for(int i=0;i<(int)pary.size();++i){ cout<<pary[i].first+1<<" "; } for(int i=pary.size()-1;i>=0;--i){ cout<<pary[i].second+1<<" "; } cout<<"\n"; pary.clear(); for(int i=0;i<n;++i)odw[i]=0; for(int i=0;i<n;++i){ if(pol[i]!=i&&!odw[i]){ pary.emplace_back(i,pol[i]); odw[i]=1;odw[pol[i]]=1; } } cout<<pary.size()*2<<"\n"; for(int i=0;i<(int)pary.size();++i){ cout<<pary[i].first+1<<" "; } for(int i=pary.size()-1;i>=0;--i){ cout<<pary[i].second+1<<" "; } } } |
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