Language: C++

#include <bits/stdc++.h>
using namespace std;
 
#define REP(i, s) for (int i = 0; i < s; ++i)
#define ALL(v) (v).begin(), (v).end()
#define COUT(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << endl
#define EACH(i, s) for (__typeof__((s).begin()) i = (s).begin(); i != (s).end(); ++i)
#define DEBUG
#define int long long
#define INF 1e18
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<class T1, class T2> ostream& operator << (ostream &s, pair<T1,T2> P)
{ return s << '<' << P.first << ", " << P.second << '>'; }
template<class T> ostream& operator << (ostream &s, vector<T> P)
{ for (int i = 0; i < P.size(); ++i) { if (i > 0) { s << " "; } s << P[i]; } return s; }
template<class T> ostream& operator << (ostream &s, vector<vector<T> > P)
{ for (int i = 0; i < P.size(); ++i) { s << endl << P[i]; } return s << endl; }
template<class T> ostream& operator << (ostream &s, set<T> P)
{ EACH(it, P) { s << "<" << *it << "> "; } return s << endl; }
template<class T1, class T2> ostream& operator << (ostream &s, map<T1,T2> P)
{ EACH(it, P) { s << "<" << it->first << "->" << it->second << "> "; } return s << endl; }
template<class T>void show(vector<T>v){for (int i = 0; i < v.size(); i++){cerr<<v[i]<<" ";}cerr<<"\n";}
typedef long long ll;

signed main()
{
    int n;
    cin >> n;
    vector<int> a(n);
    for (int i = 0; i < n; i++)
    {
        cin >> a[i];
    }
    int max_index = 0, min_index = 0;
    int maxn = 0, minn = INF;
    for (int i = 0; i < n; i++)
    {
        if(a[i] > maxn){
            maxn = a[i];
            max_index = i;
        }
        if(a[i]<minn){
            minn = a[i];
            min_index = i;
        }
    }
    vector<pair<int, int>> v;
    if(maxn>=0 && minn<=0){
    if (abs(maxn) >= abs(minn))
    {
        for (int i = 0; i < n; i++)
        {
            v.emplace_back(max_index, i);
            a[i] += maxn;
        }
        for (int i = 0; i < n-1; i++)
        {
            if(a[i]>a[i+1]){
                v.emplace_back(i, i + 1);
                a[i + 1] += a[i];
            }
            //show(a);
        }
        
    }
    else{
        for (int i = 0; i < n; i++)
        {
            v.emplace_back(min_index, i);
            a[i] += minn;
        }
        for (int i = 0; i < n-1; i++)
        {
            if(a[i]>a[i+1]){
                v.emplace_back(i + 1 , i);
                a[i] += a[i+1];
            }
        }
        }
    }
    else if(minn>0){
        for (int i = 0; i < n - 1; i++)
        {
            if (a[i] > a[i + 1])
            {
                v.emplace_back(i, i + 1);
                a[i + 1] += a[i];
            }
    }
    else{
        for (int i = 0; i < n - 1; i++)
        {
            if (a[i] > a[i + 1])
            {
                v.emplace_back(i + 1, i);
                a[i] += a[i + 1];
            }
        }
    }

   
    cout << v.size() << endl;
    for (int i = 0; i < v.size(); i++)
    {
        cout << v[i].first + 1LL << " " << v[i].second + 1LL << endl;
    }

    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:91:5: error: expected '}' before 'else'
   91 |     else{
      |     ^~~~
a.cc:82:20: note: to match this '{'
   82 |     else if(minn>0){
      |                    ^