#include <bits/stdc++.h>
#define int long long 
#define pii pair<int,int>
#define fi first
#define se second
#define pb push_back
using namespace std;
const int INF=1e6+5;
int n,m,a[INF],L[INF],R[INF],vis[INF];
set <int> s;
void del(int x) {
	L[R[x]]=L[x];
	R[L[x]]=R[x];
}
void solve() {
	s.clear();
	cin>>n>>m;
	for (int i=0;i<=n+3;i++) vis[i]=0;
	R[0]=1;L[n+1]=n;
	for (int i=1;i<=n;i++) 
		cin>>a[i],L[i]=i-1,R[i]=i+1;
	vector < pii > res;
	int ans=0;
	for (int i=1;i<n;i++)
		if (a[i+1]!=a[i]) ans++,res.pb({i,i+1});
	for (int i=1;i<=n;i++) vis[a[i]]++;
	for (int i=2;i<n;i++) {
		if (a[i-1]!=a[i+1]) 
			s.insert(i);
	}
	while (R[R[0]]<n) {
		if (s.size()) {
			int x=*s.begin();
			if (vis[a[x]]--==1) {
				for (int i=R[0];i<=n;i=R[i]) 
					if (i!=x) {
						ans++;
						res.pb({i,x});
					}
				if (a[1]!=a[n]) ans++,res.pb({1,n});
				for (pii &it:res)
					if (it.fi>it.se) swap(it.fi,it.se);
				sort(res.begin(),res.end());
				res.erase(unique(res.begin(),res.end()),res.end());
				cout<<res.size()<<"\n";
				for (auto it:res)
					cout<<it.fi<<" "<<it.se<<"\n";
				return ;
			}
			if (L[x]>1 && s.find(L[x])!=s.end()) s.erase(L[x]);
			if (R[x]<n && s.find(R[x])!=s.end()) s.erase(R[x]);
			del(x);ans++;res.pb({L[x],R[x]});
			s.erase(x);
			if (L[x]>1 && a[L[L[x]]]!=a[R[L[x]]]) s.insert(L[x]);
			if (R[x]<n && a[R[R[x]]]!=a[L[R[x]]]) s.insert(R[x]);	
		}
		else {
			int x=R[R[0]];
			if (L[x]>1 && s.find(L[x])!=s.end()) s.erase(L[x]);
			if (R[x]<n && s.find(R[x])!=s.end()) s.erase(R[x]);
			del(x);
			if (L[x]>1 && a[L[L[x]]]!=a[R[L[x]]]) s.insert(L[x]);
			if (R[x]<n && a[R[R[x]]]!=a[L[R[x]]]) s.insert(R[x]);	
		}
	}
	cout<<ans<<"\n";
	for (auto it:res)
		cout<<it.fi<<" "<<it.se<<"\n";
}
signed main()
{
	ios::sync_with_stdio(false);
	int t=0;cin>>t;
	while (t--) solve();
	return 0;
}