#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using i128 = __int128;
using u128 = unsigned __int128;
template <typename T>
void chkmax(T &x, const T &y) {
  if (x < y) x = y;
}
template <typename T>
void chkmin(T &x, const T &y) {
  if (y < x) x = y;
}
constexpr int MAXN = 2e5 + 10;
int n, m, a[MAXN], mp[MAXN], pre[MAXN], nxt[MAXN], qu[MAXN], hd, tl;
bool vis[MAXN];
pair<int, int> ans[MAXN * 2];
bool check(int u) { return a[pre[u]] != a[nxt[u]]; }
void push(int u) {
  if (vis[u]) return;
  if (check(u)) {
    vis[u] = true;
    qu[tl++] = u;
    if (tl == MAXN) tl = 0;
  }
}
void erase(int u) {
  nxt[pre[u]] = nxt[u];
  pre[nxt[u]] = pre[u];
  push(pre[u]);
  push(nxt[u]);
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int cas;
  cin >> cas;
  while (cas--) {
    cin >> n >> m;
    for (int i = 1; i <= n; ++i) cin >> a[i];
    fill(mp + 1, mp + m + 1, 0);
    for (int i = 1; i <= n; ++i) mp[a[i]] = 1;
    for (int i = 2; i <= m; ++i) mp[i] += mp[i - 1];
    m = mp[m];
    for (int i = 1; i <= n; ++i) a[i] = mp[a[i]];
    for (int i = 1; i <= n; ++i) {
      pre[i] = i - 1;
      nxt[i] = i + 1;
    }
    fill(vis + 1, vis + n + 1, false);
    vis[1] = vis[n] = true;
    hd = tl = 0;
    for (int i = 1; i <= n; ++i) push(i);
    int tp = 0;
    for (int i = 1; i < n; ++i)
      if (a[i] != a[i + 1]) ans[++tp] = {i, i + 1};
    for (int turn = 1; turn <= n - 2; ++turn) {
      while (hd != tl && !check(qu[hd])) {
        vis[qu[hd++]] = false;
        if (hd == MAXN) hd = 0;
      }
      if (hd == tl) {
        erase(nxt[1]);
      } else {
        int u = qu[hd++];
        if (hd == MAXN) hd = 0;
        vis[u] = false;
        ans[++tp] = {pre[u], nxt[u]};
        erase(u);
      }
    }
    cout << tp << "\n";
    for (int i = 1; i <= tp; ++i) cout << ans[i].first << " " << ans[i].second << "\n";
  }
  return 0;
}
/*
g++ F.cpp -o F -std=c++14 -O2 -Wall -Wextra -Wshadow -g -fsanitize=address,undefined
*/