#include<bits/stdc++.h>
using namespace std;
#define rep(i,x,y) for (int i=(x);i<=(y);i++)
#define drep(i,y,x) for (int i=(y);i>=(x);i--)
#define pii pair<int,int>
#define fir first
#define sec second
#define MP make_pair
template<typename T> bool chkmin(T &x,T y){return x>y?x=y,1:0;}
template<typename T> bool chkmax(T &x,T y){return x<y?x=y,1:0;}
void file() {
    #ifdef zqj
    freopen("a.in","r",stdin);
    #endif
}
typedef long long ll;
#define sz 202020

int n,MX;
int a[sz];
int b[sz],pos[sz],m;
int cnt[sz];

void work() {
    cin>>n>>MX; 
    rep(i,1,n) cin>>a[i];
    vector<pii>ans;
    if (a[1]==a[n]) {
        int k=n;
        while (k&&a[k]==a[n]) --k;
        if (!k) {
            cout<<"0\n";
            return;
        }
        rep(i,k+1,n) ans.push_back({k,i});
        n=k;
    }
    rep(i,1,n-1) if (a[i]!=a[i+1]) ans.push_back({i,i+1});
    m=0;
    for (int l=1,r;l<=n;l=r+1) {
        for (r=l;r!=n&&a[r+1]==a[r];r++);
        if (r!=n) {
            rep(i,l,r) ans.push_back({i,r+1});
            b[++m]=a[l],pos[m]=l;
        }
        else {
            rep(i,l,r) ans.push_back({pos[m],i});
            b[++m]=a[r],pos[m]=r;
        }
    }
    n=m;
    rep(i,1,n-1) ans.push_back({pos[i],pos[i+1]});
    rep(i,1,n) ++cnt[b[i]];
    int cc=0;
    rep(i,1,MX) cc+=!!cnt[i];
    if (cc>=3) {
        ans.push_back({pos[1],pos[n]});
        int L=1;
        rep(i,2,n-1) if (b[i]!=b[L]&&b[i]!=b[n]) {
            rep(j,L,i-1) --cnt[b[j]];
            if (cnt[b[L]]) {
                rep(j,L,i-1) ans.push_back({pos[j],pos[i]});
                ans.push_back({pos[i],pos[n]});
                L=i;
            }
            else {
                rep(j,i,n) ans.push_back({pos[L],pos[j]});
                rep(j,L+1,i-1) ans.push_back({pos[j],pos[i]});
                break;
            }
        }
    }
    else {
        for (int i=4;i<=n;i+=2) ans.push_back({pos[1],pos[i]});
    }
    sort(ans.begin(),ans.end()),ans.erase(unique(ans.begin(),ans.end()),ans.end());
    cout<<ans.size()<<'\n';
    for (auto [x,y]:ans) cout<<x<<' '<<y<<'\n';

    // {
         for (auto [x,y]:ans) assert(a[x]!=a[y]);
    //     for (auto [x,y]:ans) for (auto [l,r]:ans) if (l<x) assert(!(x<r&&r<y));
    // }


    rep(i,1,n) a[i]=b[i]=pos[i]=0;
    rep(i,0,MX) cnt[i]=0;
}

int main() {
    file();
    ios::sync_with_stdio(false),cin.tie(0);
    int T; cin>>T;
    while (T--) work();
    return 0;
}