Problem: 2052A - Adrenaline Rush
Language: java

Solution 1 (runtime: 546 ms):
#include<bits/stdc++.h>
#define LOCAL
#ifdef LOCAL
#if __has_include("C:\Users\HP\Desktop\Codeforces\template.cpp")
#include "C:\Users\HP\Desktop\Codeforces\template.cpp"
#else
#pragma message("template.cpp not found. Proceeding without it.")
#endif
#else
#define debug(...)
#endif
using namespace std;
#define out(x) cout<<x<<endl
#define in(x)  cin>>x
#define yes cout<<"YES"<<endl
#define no cout<<"NO"<<endl
#define int long long
#define pb(x) push_back(x)
#define all(x) x.begin(),x.end()
#define deb(x) cout<<"#"<<x<<endl
#define deb2(x) cout<<"^"<<x<<endl
#define rep(i,x,y) for(int i=x;i<y;i++)
#define nxt cout<<endl;
#define vi vector<int>
#define vp vector<pair<int,int>>
#define vvi vector<vector<int>>
#define vc vector<char>

void solve(){
int n;
in(n);
vi v(n);
rep(i,0,n){
    in(v[i]);
}
if(n==1){
    out(0);
    return;
}
int cnt=0;
vp pp;
map<pair<int,int>,int>mp;
map<pair<int,int>,int>mpp;
for(int i=0;i<n;i++){
    for(int j=i+1;j<n;j++){
        if(v[i]>v[j]){
            cnt++;
            pp.push_back({v[i],v[j]});
        }else{
            cnt+=2;
            pp.push_back({v[i],v[j]});
            pp.push_back({v[j],v[i]});
        }
    }
}
vi tmp(n+1);
for(int i=1;i<=n;i++){
    tmp[i]=i;
}
out(cnt);
set<pair<int,int>>ss;
for(int i=0;i<pp.size();i++){
    ss.insert({pp[i].first,pp[i].second});
}
for(int i=0;i<cnt;i++){ 
    for(auto &it:ss){
        int x = it.first;
        int y = it.second;
        int z2 = tmp[x]-tmp[y];
        if(z2==1){
            cout<<x<<" "<<y<<endl;
            swap(tmp[x],tmp[y]);
            auto it2 = ss.find({x,y});
            ss.erase(it2);
            break;
        }
    }
}
}

signed main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
int t=1;
// cin>>t;
while(t--){
solve();
}
}

Solution 2 (runtime: 968 ms):
//package Practice;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.*;

public class AdrenalineRush {
    public static void swap(int[] arr, int l) {
        int temp = arr[l];
        arr[l] = arr[l+1];
        arr[l+1] = temp;
    }
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw = new PrintWriter(System.out);
        int n = Integer.parseInt(br.readLine());
        int[] arr = new int[n];
        StringTokenizer st = new StringTokenizer(br.readLine());
        HashMap<Integer, Integer> map = new HashMap<>();
        for (int i = 0; i < n; i++) {
            arr[i] = Integer.parseInt(st.nextToken());
            map.put(arr[i], i);
         }
        if (n == 1) {
            pw.println("0");
            pw.close();
            return;
        }
        HashMap<Integer, Integer> map2 = new HashMap<>();
        int[] arr2 = new int[n];
        for (int i = 0; i < n; i++) {
            arr2[i] = i+1;
            map2.put(i+1, i);
        }
        ArrayList<String> moves= new ArrayList<>();
        for (int i = n-1; i >= 0; i--) {
            int curNum = arr[i];
            int startIdx = map2.get(curNum);
            int endIdx = map.get(curNum);
            // pass everything that starts in front
           // System.out.println("starting passing phase, arr2 is " + Arrays.toString(arr2) + " and curNum is " + curNum + " and start: " + startIdx);
            for (int j = startIdx-1; j >= 0; j--) {
                moves.add(arr2[j+1] + " " +  arr2[j]);
                swap(arr2, j);
                //System.out.println("passed 1, move was " + moves.getLast());
            }
            for (int j = 0; j < startIdx; j++) {
                map2.put(arr2[j], j);
            }
            startIdx = map2.get(curNum);
            // then get passed by everything that ends in front
            //System.out.println("at i="+i+", curNum is " + curNum + " and start:" + startIdx + " and end:" + endIdx);
            if (startIdx < endIdx) {
                //System.out.println("starting going back phase");
                while (startIdx < endIdx) {
                    //System.out.println("one move with num = " + curNum);
                    moves.add(arr2[startIdx+1] + " " + arr2[startIdx]);
                    int temp = arr2[startIdx];
                    map2.put(arr2[startIdx], map2.get(arr2[startIdx]) + 1);
                    map2.put(arr2[startIdx+1], map2.get(arr2[startIdx+1]) - 1);
                    arr2[startIdx] = arr2[startIdx+1];
                    arr2[startIdx+1] = temp;
                    startIdx++;
            //        pw.println("arr2:" + Arrays.toString(arr2) + " and last move was " + moves.getLast());
                }
            }
            for (int j = 0; j < startIdx; j++) {
                map2.put(arr2[j], j);
            }
          //  System.out.println("arr2 at the end of the process:" + Arrays.toString(arr2));
        }
        //System.out.println("arr2:" + Arrays.toString(arr2));
        /*HashSet<String> moveSet = new HashSet<>();
        moveSet.addAll(moves);
        for (int i = 0; i < n - 1; i++) {
            if (!moveSet.contains(arr2[i] + " " + arr2[i+1]) && !moveSet.contains(arr2[i+1] + " " + arr2[i])) {
                moves.add(arr2[i+1] + " " + arr2[i]);
                moves.add(arr2[i] + " " + arr2[i+1]);
            }
        }*/
        pw.println(moves.size());
        for (String move: moves) {
            pw.println(move);
        }
        // do extra stuff

        pw.close();
        br.close();
    }
}