Problem: 2052A - Adrenaline Rush
Language: java

Solution 1 (runtime: 749 ms):
import java.io.*;
import java.util.*;

public class Main {
    public static int INF = 0x3f3f3f3f, mod = 1000000007, mod9 = 998244353;
    public static void main(String args[]){
        try {
            PrintWriter o = new PrintWriter(System.out);
            boolean multiTest = false;
            // init
            if(multiTest) {
                int t = nextInt(), loop = 0;
                while (loop < t) {loop++;solve(o);}
            } else solve(o);
            o.close();
        } catch (Exception e) {e.printStackTrace();}
    }
    static void solve(PrintWriter o) {
        try {
            int n = nextInt();
            int[] c = new int[n];
            for(int i=0;i<n;i++) c[i] = nextInt();
            List<int[]> li = new ArrayList<>();
            int[] a = new int[n];
            Map<Integer, Integer> idxMap = new HashMap<>();
            for(int i=0;i<n;i++) {
                a[i] = i+1;
                idxMap.put(a[i], i);
            }
            for(int i=n-1;i>=0;i--) {
                int x = idxMap.get(c[i]);
                for(int j=x-1;j>=0;j--) li.add(new int[]{a[x], a[j]});
                for(int j=0;j<x;j++) li.add(new int[]{a[j], a[x]});
                for(int j=x+1;j<i+1;j++) {
                    a[j-1] = a[j];
                    idxMap.put(a[j], j-1);
                    li.add(new int[]{a[j], c[i]});
                }
                a[i] = c[i];
                idxMap.put(c[i], i);
            }
            o.println(li.size());
            for(int[] it: li) o.println(it[0] + " " + it[1]);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    public static int upper_bound(List<Integer> a, int val){
        int l = 0, r = a.size();
        while(l < r){
            int mid = l + (r - l) / 2;
            if(a.get(mid) <= val) l = mid + 1;
            else r = mid;
        }
        return l;
    }
    public static int lower_bound(List<Integer> a, int val){
        int l = 0, r = a.size();
        while(l < r){
            int mid = l + (r - l) / 2;
            if(a.get(mid) < val) l = mid + 1;
            else r = mid;
        }
        return l;
    }
    public static long gcd(long a, long b){
        return b == 0 ? a : gcd(b, a%b);
    }
    public static long lcm(long a, long b){
        return a / gcd(a,b)*b;
    }
    public static long qpow(long a, long n, int md){
        a %= md;
        long ret = 1l;
        while(n > 0){
            if((n & 1) == 1){
                ret = ret * a % md;
            }
            n >>= 1;
            a = a * a % md;
        }
        return ret;
    }
    public static class FenWick {
        int n;
        long[] a;
        long[] tree;
        public FenWick(int n){
            this.n = n;
            a = new long[n+1];
            tree = new long[n+1];
        }
        private void add(int x, long val){
            while(x <= n){
                tree[x] += val;
                x += x&-x;
            }
        }
        private void addMx(int x, long val) {
            a[x] += val;
            tree[x] = a[x];
            while(x <= n) {
                for(int i=1;i<(x&-x);i<<=1) {
                    tree[x] = Math.max(tree[x], tree[x-i]);
                }
                x += x&-x;
            }
        }
        private long query(int x){
            long ret = 0l;
            while(x > 0){
                ret += tree[x];
                x -= x&-x;
            }
            return ret;
        }
        private long queryMx(int l, int r) {
            long res = 0l;
            while(l <= r) {
                if(r-(r&-r) >= l) {
                    res = Math.max(res, tree[r]);
                    r -= r&-r;
                }
                else {
                    res = Math.max(res, a[r]);
                    r--;
                }
            }
            return res;
        }
    }
    public static class Pair{
        Integer c1;
        Integer c2;
        public Pair(Integer c1, Integer c2) {
            this.c1 = c1;
            this.c2 = c2;
        }
        @Override
        public int hashCode() {
            int prime = 31, ret = 1;
            ret = ret*prime + c1.hashCode();
            ret = ret*prime + c2.hashCode();
            return ret;
        }
        @Override
        public boolean equals(Object obj) {
            if(obj instanceof Pair) {
                return c1.equals(((Pair) obj).c1) && c2.equals(((Pair) obj).c2);
            }
            return false;
        }
    }
    private static BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
    private static StringTokenizer tokenizer = new StringTokenizer("");
    private static String next() throws IOException{
        while(!tokenizer.hasMoreTokens()){tokenizer = new StringTokenizer(reader.readLine());}
        return tokenizer.nextToken();
    }
    public static int nextInt() throws IOException {return Integer.parseInt(next());}
    public static Long nextLong() throws IOException {return Long.parseLong(next());}
    public static double nextDouble() throws IOException {return Double.parseDouble(next());}
    public static char nextChar() throws IOException {return next().toCharArray()[0];}
    public static String nextString() throws IOException {return next();}
    public static String nextLine() throws IOException {return reader.readLine();}
}

Solution 2 (runtime: 1249 ms):

import java.io.*;
import java.util.*;

public class ComTemp2 {

    private static final long MINA = 1;
    private static final long MAXA = 1000000000000L;
    static BufferedReader reader;
    static StringTokenizer tokenizer;
    static PrintWriter writer;

    static int MOD = (int) (1e9 + 7);
    static final int MOD1 = 998244353;

    public static Scanner scanner = new Scanner(System.in);

    public static boolean flag1 = true, flag2 = true;

    public static void main(String[] args) throws IOException {
        reader = new BufferedReader(new InputStreamReader(System.in));
        writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
        tokenizer = new StringTokenizer("");

//        int n = nextInt();
        int n = 1;
        while (n-- > 0) {
            solve();
        }

        writer.close();
    }


    static int fun(int a1, int a2, int a3, int a4, int a5) {
        int count = 0;
        if (a3 == a1 + a2) count++;
        if (a4 == a2 + a3) count++;
        if (a5 == a3 + a4) count++;
        return count;
    }

    public static void solve() throws IOException {
        int n = nextInt();
        long[] arr = nextLongArray(n);
        ArrayList<Pair<Long, Long>> list = new ArrayList<>();
        Pair<Long, Long>[] res = new Pair[n];
        for (int i = 0; i < n; i++) {
            res[i] = new Pair<>(arr[i], i + 1L);
        }
        for (int i = n; i > 0; i--) {
            int j = 0;
            while (arr[j] != i) {
                j++;
            }

            for (int k = j; k > 0; k--) {
                long tem = arr[k];
                arr[k] = arr[k - 1];
                arr[k - 1] = tem;
                list.add(new Pair<>(arr[k], arr[k - 1]));
            }

            for (int k = 0; k < i - 1; k++) {
                long tem = arr[k];
                arr[k] = arr[k + 1];
                arr[k + 1] = tem;
                list.add(new Pair<>(arr[k + 1], arr[k]));
            }
        }

        int s = list.size();
        writer.println(s);
        for (int i = s-1; i >= 0; i--) {
            writer.println(list.get(i).key + " " + list.get(i).value);
        }
    }

    public static void solv() throws IOException {
        int n = nextInt();
        for (int i = 0; i < 2; i++) {
            writer.print(1 + " ");
        }
        for (int i = 2; i < n - 1; i++) {
            writer.print(i + " ");
        }
        writer.println(1);
    }

    public static boolean isPowerLogarithmic(int x, int y) {
        if (x <= 0 || y <= 0 || y == 1) return false; // Edge cases

        double logResult = Math.log(x) / Math.log(y);
        return Math.abs(logResult - Math.round(logResult)) < 1e-10;
    }


/*
14
10100001000101
15
001110100100001
14
10100101111101

11
01100101101
14
01001111101001
 */

    private static int ask(int l, int r) throws IOException {
        if (r - l + 1 <= 1)
            return 0;
        writer.println(String.valueOf("? ") + String.valueOf(l) + " " + String.valueOf(r));
        writer.flush();
        return nextInt();
    }

    public static int leftmostBit(int n) {
        return (int) Math.pow(2, (int) (Math.log(n) / Math.log(2)));
    }

    public static int leftmostBit(long n) {
        return (int) Math.pow(2, (long) (Math.log(n) / Math.log(2)));
    }

    public static long gcdOfArray(int[] arr) {
        long result = arr[0];
        for (int i = 1; i < arr.length; i++) {
            result = gcd(result, arr[i]);
            if (result == 1)
                break; // Early exit if GCD is 1
        }
        return result;
    }

    static long gcd(long a, long b) {
        return b == 0 ? a : gcd(b, a % b);
    }

    public static List<Integer> findDivisors(int n) {
        List<Integer> divisors = new ArrayList<>();

        for (int i = 1; i <= Math.sqrt(n); i++) {
            if (n % i == 0) {
                divisors.add(i); // Add the divisor
                if (i != n / i) { // Avoid duplicate for perfect squares
                    divisors.add(n / i);
                }
            }
        }

        // Optional: Sort the divisors if needed
        divisors.sort(Integer::compareTo);
        return divisors;
    }

    public static long[] unique(long[] arr) {
        int n = arr.length;
        ArrayList<Long> l1 = new ArrayList<>();
        l1.add(arr[0]);
        for (int i = 1; i < n; i++) {
            if (arr[i] == arr[i - 1]) {
                continue;
            } else {
                l1.add(arr[i]);
            }
        }
        n = l1.size();
        long[] tem = new long[n];
        for (int i = 0; i < n; i++) {
            tem[i] = l1.get(i);
        }
        return tem;
    }

    public static void reverseArray(long[] array) {
        int start = 0, end = array.length - 1;
        while (start < end) {
            long temp = array[start];
            array[start] = array[end];
            array[end] = temp;
            start++;
            end--;
        }
    }

    public static <T> void printArr(int[] arr) {
        for (int e : arr) {
            writer.print(e + " ");
        }
        writer.println();
    }

    public static void printArr(long[] arr) {
        for (long e : arr) {
            writer.print(e + " ");
        }
        writer.println();
    }

    private static int lowerBound(long[] arr, long target, int start, int end) {
        int left = start, right = end;
        while (left <= right) {
            int mid = left + (right - left) / 2;
            if (arr[mid] < target) {
                left = mid + 1;
            } else {
                right = mid - 1;
            }
        }
        return left;
    }

    // Binary search for the last index where arr[index] <= target
    private static int upperBound(long[] arr, long target, int start, int end) {
        int left = start, right = end;
        while (left <= right) {
            int mid = left + (right - left) / 2;
            if (arr[mid] <= target) {
                left = mid + 1;
            } else {
                right = mid - 1;
            }
        }
//        if (arr[right]>target)return -1;
        return right;
    }

    public static class Pair<K, V> {
        private K key;
        private V value;

        public Pair(K key, V value) {
            this.key = key;
            this.value = value;
        }

        public K getKey() {
            return key;
        }

        public void setKey(K key) {
            this.key = key;
        }

        public V getValue() {
            return value;
        }

        public void setValue(V value) {
            this.value = value;
        }

        @Override
        public String toString() {
            return "Pair{" + "key=" + key + ", value=" + value + '}';
        }
    }

    static String next() throws IOException {
        while (!tokenizer.hasMoreTokens()) {
            tokenizer = new StringTokenizer(reader.readLine());
        }
        return tokenizer.nextToken();
    }

    static String nextLine() throws IOException {
        return reader.readLine();
    }

    static int nextInt() throws IOException {
        return Integer.parseInt(next());
    }

    static long nextLong() throws IOException {
        return Long.parseLong(next());
    }

    static int[] nextIntArray(int n) throws IOException {
        int[] arr = new int[n];
        for (int i = 0; i < n; i++) {
            arr[i] = nextInt();
        }
        return arr;
    }

    // Function to read the next array of longs
    static long[] nextLongArray(int n) throws IOException {
        long[] arr = new long[n];
        for (int i = 0; i < n; i++) {
            arr[i] = nextLong();
        }
        return arr;
    }

    static double nextDouble() throws IOException {
        return Double.parseDouble(next());
    }
}