#include<iostream>
#include<cstdio>
#include<algorithm>
#include<set>
#define rep(i, a, b) for(int i = (a); i <= (b); i++)
#define per(i, a, b) for(int i = (a); i >= (b); i--)
using namespace std;
const int N = 200010;
int n, m, a[N], tot, pre[N], nxt[N], cnt[N], ans;
set<int> s;

inline bool check(int x){
    if(x == 1 || x == n) return 0;
    return a[pre[x]] != a[nxt[x]];
}
inline void del(int x, bool flag){
    if(!flag) ans += check(x);
    else if(check(x)) printf("%d %d\n", pre[x], nxt[x]);
    cnt[x]--, tot++;
    nxt[pre[x]] = nxt[x], pre[nxt[x]] = pre[x];
}

void calc(bool flag){
    rep(i, 2, n - 1) if(check(i)) s.insert(i);
    while(tot < n - 2){
        if(s.empty()){
            del(nxt[1], flag);
            if(check(nxt[1])) s.insert(nxt[1]);
            continue;
        }
        int x = *s.begin(); s.erase(s.begin());
        if(cnt[x] == 1){
            if(pre[x] != 1) del(pre[x], flag);
            else if(nxt[x] != n) del(nxt[x], flag);
            else del(x, flag);
            continue;
        }
        del(x, flag); int y = pre[x], z = nxt[x];
        bool t1 = check(y), t2 = check(z);
        if(t1 && !s.count(y)) s.insert(y);
        if(!t1 && s.count(y)) s.erase(s.find(y));
        if(t2 && !s.count(z)) s.insert(z);
        if(!t2 && s.count(z)) s.erase(s.find(z));
    }
}

void solve(){
    ans = 0, tot = 0;
    scanf("%d%d", &n, &m);
    rep(i, 1, n){
        scanf("%d", &a[i]);
        pre[i] = i - 1, nxt[i] = i + 1;
        cnt[i] = 0;
    }
    s.clear();
    rep(i, 1, n - 1) ans += (a[i] != a[i + 1]);
    calc(0);
    printf("%d\n", ans);
    rep(i, 1, n) pre[i] = i - 1, nxt[i] = i + 1, cnt[i] = 0;
    s.clear(); tot = 0;
    rep(i, 1, n - 1) if(a[i] != a[i + 1])
        printf("%d %d\n", i, i + 1);
    calc(1);
}

int main(){
    int T; scanf("%d", &T); while(T--) solve();
    return 0;
}