#include <bits/stdc++.h>
#define all(x) x.begin(), x.end()
#define pb push_back
#define eb emplace_back
#define MP make_pair
#define MT make_tuple
#define IT iterator
#define fi first
#define se second
#define For(i, a, b) for (int i = (int)(a); i <= (int)(b); ++i)
#define Rep(i, a, b) for (int i = (int)(a); i >= (int)(b); --i)
#define CLR(a, v) memset(a, v, sizeof(a))
#define CPY(a, b) memcpy(a, b, sizeof(a))
#define debug cerr << "ztxakking\n"
#define y0 ztxaknoi
#define y1 ztxakioi
using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;
using uint = unsigned int;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pli = pair<ll, int>;
using pil = pair<int, ll>;
using vi = vector<int>;
template<typename T>
using V = vector<T>;
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
const int N = 2e5 + 7;
int n, m, a[N], pre[N], nxt[N], cnt[N];
void del(int u) {
  nxt[pre[u]] = nxt[u], pre[nxt[u]] = pre[u];
}
set<int> s;
V<pii> ans;
void push(int x, int y) {
  ans.eb(x, y);
}
void print() {
  cout << ans.size() << '\n';
  for (auto [x, y] : ans) cout << x << ' ' << y << '\n';
}
void sol() {
  cin >> n >> m, ans.clear();
  For(i, 1, m) cnt[i] = 0;
  For(i, 1, n) cin >> a[i], ++cnt[a[i]];
  For(i, 1, n - 1) if (a[i] != a[i + 1]) push(i, i + 1);
  For(i, 2, n - 1) pre[i] = i - 1, nxt[i] = i + 1;
  nxt[1] = 2, pre[n] = n - 1, s.clear();
  For(i, 2, n - 1) if (a[pre[i]] != a[nxt[i]]) s.insert(i);
  for (int t = n - 2; t; --t) {
    if (s.size()) {
      int u = *s.begin(); s.erase(s.begin());
      if (cnt[a[u]] == 1) {
        for (int i = pre[u]; i > 1; i = pre[i]) push(pre[i], nxt[i]), del(i);
        for (int i = nxt[u]; i < n; i = nxt[i]) push(pre[i], nxt[i]), del(i);
        if (a[1] != a[n]) push(1, n);
        break;
      } else {
        push(pre[u], nxt[u]);
        int x = pre[u], y = nxt[u];
        del(u);
        if (x > 1 && a[pre[x]] != a[nxt[x]]) s.insert(x);
        else {
          if (s.find(x) != s.end()) s.erase(x);
        }
        if (y < n && a[pre[y]] != a[nxt[y]]) s.insert(y);
        else {
          if (s.find(y) != s.end()) s.erase(y);
        }
      }
    } else {
      int u = nxt[1], v = nxt[u];
      del(u);
      if (v < n && a[1] != a[nxt[v]]) s.insert(v);
    }
  }
  print();
}
int main() {
  ios::sync_with_stdio(0), cin.tie(0);
  int t; cin >> t;
  while (t--) sol();
  return 0;
}