#include <bits/stdc++.h>
using namespace std;
int n;
const int MAX_N = 3010;
vector<int> good_place;
int should_be_in[MAX_N];
vector<vector<int> > result;
int tab[MAX_N];
int where_is[MAX_N];
void exchange(int a, int b, vector<bool> &moved, vector<int> &bg, vector<int> &ed){
moved[tab[a]] = true;
moved[tab[b]] = true;
bg.push_back(a+1);
ed.push_back(b+1);
where_is[tab[a]] = b;
where_is[tab[b]] = a;
swap(tab[a], tab[b]);
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n;
for(int i=0; i<n; i++){
cin >> tab[i];
good_place.push_back(tab[i]);
}
sort(good_place.begin(), good_place.end());
for(int i=0; i<n; i++) should_be_in[good_place[i]] = i;
for(int i=0; i<n; i++) where_is[tab[i]] = i;
while(true){
vector<bool> moved(MAX_N, false);
vector<int> bg;
vector<int> ed;
for(int i=0; i<n; i++){
if(should_be_in[tab[i]] != i && !moved[tab[i]] && !moved[tab[should_be_in[tab[i]]]]){
// cout << "------ " << i+1 << " -------" << endl;
// cout << "exchanging: " << i+1 << " " << should_be_in[tab[i]]+1 << endl;
exchange(i, should_be_in[tab[i]], moved, bg, ed);
int j = i;
// cout << good_place[j] << " " << tab[j] << endl;
while(good_place[j] != tab[j]){
int a = where_is[good_place[j]];
int move_to = should_be_in[tab[j]];
if(a == move_to) break;
// cout << "------ (j) " << j+1 << " -------" << endl;
// cout << "exchanging2: " << i+1 << " " << should_be_in[tab[i]]+1 << endl;
exchange(a, move_to, moved, bg, ed);
j = a;
}
}
}
vector<int> tmp_res;
if(bg.size() == 0) break;
for(int i=0; i<bg.size(); i++) tmp_res.push_back(bg[i]);
for(int i=ed.size()-1; i>=0; i--) tmp_res.push_back(ed[i]);
result.push_back(tmp_res);
}
cout << result.size() << endl;
for(int i=0; i<result.size(); i++){
cout << result[i].size() << endl;
for(int j=0; j<result[i].size(); j++){
cout << result[i][j] << " ";
}
cout << endl;
}
return 0;
}
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 | #include <bits/stdc++.h> using namespace std; int n; const int MAX_N = 3010; vector<int> good_place; int should_be_in[MAX_N]; vector<vector<int> > result; int tab[MAX_N]; int where_is[MAX_N]; void exchange(int a, int b, vector<bool> &moved, vector<int> &bg, vector<int> &ed){ moved[tab[a]] = true; moved[tab[b]] = true; bg.push_back(a+1); ed.push_back(b+1); where_is[tab[a]] = b; where_is[tab[b]] = a; swap(tab[a], tab[b]); } int main(){ ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); cin >> n; for(int i=0; i<n; i++){ cin >> tab[i]; good_place.push_back(tab[i]); } sort(good_place.begin(), good_place.end()); for(int i=0; i<n; i++) should_be_in[good_place[i]] = i; for(int i=0; i<n; i++) where_is[tab[i]] = i; while(true){ vector<bool> moved(MAX_N, false); vector<int> bg; vector<int> ed; for(int i=0; i<n; i++){ if(should_be_in[tab[i]] != i && !moved[tab[i]] && !moved[tab[should_be_in[tab[i]]]]){ // cout << "------ " << i+1 << " -------" << endl; // cout << "exchanging: " << i+1 << " " << should_be_in[tab[i]]+1 << endl; exchange(i, should_be_in[tab[i]], moved, bg, ed); int j = i; // cout << good_place[j] << " " << tab[j] << endl; while(good_place[j] != tab[j]){ int a = where_is[good_place[j]]; int move_to = should_be_in[tab[j]]; if(a == move_to) break; // cout << "------ (j) " << j+1 << " -------" << endl; // cout << "exchanging2: " << i+1 << " " << should_be_in[tab[i]]+1 << endl; exchange(a, move_to, moved, bg, ed); j = a; } } } vector<int> tmp_res; if(bg.size() == 0) break; for(int i=0; i<bg.size(); i++) tmp_res.push_back(bg[i]); for(int i=ed.size()-1; i>=0; i--) tmp_res.push_back(ed[i]); result.push_back(tmp_res); } cout << result.size() << endl; for(int i=0; i<result.size(); i++){ cout << result[i].size() << endl; for(int j=0; j<result[i].size(); j++){ cout << result[i][j] << " "; } cout << endl; } return 0; } |
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