Problem: 2052A - Adrenaline Rush
Language: java

Solution 1 (runtime: 1953 ms):
import java.util.*;
import java.io.*;

public class A_Adrenaline_Rush {

    int mod = (int) 1e9 + 7;
    
    public static void main(String[] args) {
        int n = sc.nextInt();
        int[] f = new int[n];
        input(f);
        int[] a = new int[n];
        for(int i=0;i<n;i++) a[i] = i+1;
        List<int[]> l = new ArrayList<>();
        for(int i=1;i<n;i++){
            int j = i;
            while(j>0){
                int temp = a[j];
                a[j] = a[j-1];
                a[j-1] = temp;
                l.add(new int[]{a[j-1],a[j]});
                j--;
            }
        }
        for(int i=0;i<n;i++){
            int pl = f[i];
            // System.out.println(pl);
            int idx = -1;
            for(int j=0;j<n;j++){
                if(a[j]==pl){
                    idx = j;
                    break;
                }
            }
            // System.out.println(idx);
            if(i<idx)    {int j = idx;
                while(j>i){
                    int temp = a[j];
                    a[j] = a[j-1];
                    a[j-1] = temp;
                    l.add(new int[]{a[j-1],a[j]});
                    j--;
                }
                // if(dest>0){
                //     while(j<dest){
                //         int temp = a[j];
                //         a[j] = a[j+1];
                //         a[j+1] = temp;
                //         l.add(new int[]{a[j],a[j+1]});
                //         j++;
                //     }
                // }
            }
            // printArr(a);
        }
        System.out.println(l.size());
        for(int i=0;i<l.size();i++){
            System.out.println(l.get(i)[0] + " " + l.get(i)[1]);
        }
        // printArr(a);
    }
    
    public static void input(Object array) {
        if (array instanceof int[])
            for (int i = 0; i < ((int[]) array).length; i++)
                ((int[]) array)[i] = sc.nextInt();
        else if (array instanceof long[])
            for (int i = 0; i < ((long[]) array).length; i++)
                ((long[]) array)[i] = sc.nextLong();
    }
    
    public static void printArr(Object array) {
        if (array instanceof int[])
            for (int x : (int[]) array)
                System.out.print(x + " ");
        else if (array instanceof long[])
            for (long x : (long[]) array)
                System.out.print(x + " ");
        System.out.println();
    }
    
    public static <T extends Number> long gcd(T a, T b) {
        return b.longValue() == 0 ? a.longValue() : gcd(b, a.longValue() % b.longValue());
    }
    
    static FastReader sc = new FastReader();
    
    static class FastReader {
        BufferedReader br;
        StringTokenizer st;
    
        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }
    
        String next() {
            while (st == null || !st.hasMoreTokens()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
    
        int nextInt() {
            return Integer.parseInt(next());
        }
    
        long nextLong() {
            return Long.parseLong(next());
        }
    
        double nextDouble() {
            return Double.parseDouble(next());
        }
    
        String nextLine() {
            String str = "";
            try {
                str = br.readLine().trim();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return str;
        }
    }
}

Solution 2 (runtime: 1983 ms):
import java.util.*;
public class AdrenalinRush{
public static void print(Object print){
    System.out.print(print);
}
public static void println(Object print){
    System.out.println(print);
}
public static void println(){
    System.out.println();
}
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int[] a = new int[n];
    int[] b = new int[n];
    HashMap<Integer, Integer> map = new HashMap<>();
    HashMap<Integer, Integer> map2 = new HashMap<>();
    ArrayList<int[]> arr = new ArrayList<>();
    int ans=0;
    for(int i=0; i<n; i++){
        a[i]=sc.nextInt();
        map.put(i, a[i]);
        map2.put(i+1, n-i-1);
        b[i]=n-i;
    }
    for(int i=1; i<=n; i++){
        for(int j=i+1; j<=n; j++){
            arr.add(new int[]{j, i});
            // println(j+" "+i);
        }
    }
    ans+=n*(n-1)/2;
    for(int j=n-1; j>=0; j--){
        int tar = map.get(j);
        int curr = map2.get(tar);
        for(int i=curr; i<j; i++){
            ans++;
            // println(b[i+1]+" "+b[i]);
            arr.add(new int[]{b[i+1], b[i]});
            int temp=b[i];
            b[i]=b[i+1];
            b[i+1]=temp;
            map2.put(b[i], i);
            map2.put(b[i+1], i+1);
        }
    }
    println(ans);
    for(int[] i: arr){
        println(i[0]+" "+i[1]);
    }

}
}