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
#include<bits/stdc++.h>
using namespace std;

int main(){
	int n;
	cin >> n;
	vector<int> a, sa;
	for(int i = 0 ;i < n; i++){
		int temp;
		cin >> temp;
		a.push_back(temp);
		sa.push_back(temp);
	}
	sort(sa.begin(), sa.end());
	int p[3000];
	for(int i = 0; i < n; i++) p[sa[i]-1]=i;
	int fin = 0; bool comp = 0;
	vector<int> pain;
	vector<int> pain2;
	while(!comp){
		bool changed[n]; comp = 1;
		int ctr =0;
		fin++;
		for(int i = 0; i < n; i++) changed[i] = 1;
		int i, temp;
		for(int ii = 0; ii < n; ii++){
			i=ii;
			starte:
			if(changed[i]&&changed[p[a[i]-1]]&&i!=p[a[i]-1]){
				comp=0;
				changed[i]=0;
				changed[p[a[i]-1]]=0;
				temp=a[i];
				a[i]=a[p[temp-1]];
				a[p[temp-1]]=temp;
				pain2.push_back(i+1);
				pain2.push_back(p[temp-1]+1);
				ctr+=2;
				i=p[a[i]-1];
				goto starte;
			}
		}
		if(!comp){
			pain.push_back(ctr);
		}
	}
	cout << fin-1 << '\n';
	int sum = 0;
	for(int i = 0; i < fin-1; i++){
		cout << pain[i] << '\n';
		int output[pain[i]];
		int iii = 0;
		for(int j = sum; j < sum+pain[i]; j+=2){
			output[iii]=pain2[j];
			iii++;
		}
		iii=pain[i]-1;
		for(int j = sum+1; j < sum+pain[i]; j+=2){
			output[iii]=pain2[j];
			iii--;
		}
		for(int j = 0; j < pain[i]; j++) cout << output[j] << ' ';
		cout << '\n';
		sum+=pain[i];
	}
	return 0;
}