月赛 C RE

#include <bits/stdc++.h>

using namespace std;

#define int long long
#define ls (rt << 1)
#define rs (rt << 1 | 1)
#define lowbit(x) x & -x
#define fup(x, l, r) for (int x = (l), eNd = (r); x <= eNd; ++ x )
#define fdw(x, r, l) for (int x = (r), eNd = (l); x >= eNd; -- x )
typedef long long ll;
typedef unsigned long long LL;
typedef pair<int, int> PII;

struct fastread {
	template <typename T>
	fastread& operator >>(T& x) {
		x = 0; bool flg = false; char c = getchar();
		while (c < '0' || c > '9') flg |= (c == '-'), c = getchar();
		while (c >= '0' && c <= '9') x = (x << 3) + (x << 1) + c - '0', c = getchar();
		if (flg) x = -x; return *this;
	}
	template <typename T>
	fastread& operator >>(vector<T>& x) {
		for (auto it = x.begin(); it != x.end(); ++ it ) (*this) >> *it;
		return *this;
	}
}fin;

struct fastwrite {
	template <typename T>
	fastwrite& operator <<(T x) {
		if (x < 0) x = -x, putchar('-');
		static int buf[35]; int top = 0;
		do buf[top ++ ] = x % 10, x /= 10; while (x);
		while (top) putchar(buf[ -- top] + '0');
		return *this;
	}
	fastwrite& operator <<(char x) {
		putchar(x); return *this;
	}
	template <typename T>
	fastwrite& operator <<(vector<T> x) {
		for (auto it = x.begin(); it != x.end(); ++ it ) (*this) << *it, putchar(' ');
		putchar('\n');
		return *this;
	}
}fout;

const int N = 3e6 + 10;
const int P = 998244353;

int T;
int n, k;
int a[N];
int cnt;
struct node
{
	int m, d;
}g[N], b[N];
int fpm(int a, int n)
{
	int res = 1;
	while(n)
	{
		if(n & 1)	res = res * a;
		a = a * a;
		n >>= 1;
	}
	return res;
}
int fen(int x)
{
	int cnt = 0;
	while(x)
	{
		cnt++;
		x /= 10;
	}
	return cnt;
}
bool cmp(node a, node b)
{
	if(a.m < b.m)	return 1;
	else if(a.m == b.m)	return a.d < b.d;
	else	return 0;
}

int res[N];
void solve()
{
	cnt = 0;
	memset(res, 0, sizeof res);
	memset(a, 0, sizeof a);
	memset(b, 0, sizeof b);
	fin >> n >> k;
	fup(i, 1, n)	fin >> a[i];
	if(k == 1)
	{
		fout << 0 << '\n';
		return ;
	}
	res[0] = 1;
	res[1] = k;
	int e = 0;
	fup(i, 2, 64)
	{
		if(res[i] > 1e18 || res[i] < 0)	continue;
		res[i] = res[i - 1] * k;
		e++;
	}
	//fout << e << '\n';
	fup(i, 1, e)
	{
		int len = fen(res[i]);
	//	fout << len << ' ' << res[i] << '\n';
		if(res[i] <= 10)	continue;
		fup(i, 0, len - 1)
		{
			if((res[i] / fpm(10, len - i - 1)) % 10 == 0)	continue;
			int qian = res[i] / fpm(10, len - i);
			int hou = res[i] % fpm(10, len - i);
			//fout << qian << ' ' << hou << '\n'; 
			if(qian <= n && qian != 0 && hou != 0 && hou <= a[qian])
			{
				cnt++;
				g[cnt].m = qian, g[cnt].d = hou;
			}
		}
	}
	int ans = 0;
	sort(g + 1, g + cnt + 1, cmp);
	fup(i, 1, cnt)
	{
		if(!(g[i - 1].m == g[i].m && g[i - 1].d == g[i].d))	ans++;
	}
	fout << ans << '\n';
	fup(i, 1, cnt)
	{
		if(!(g[i - 1].m == g[i].m && g[i - 1].d == g[i].d))	fout << g[i].m << ' ' << g[i].d << '\n';
	}
}

main(void)
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	fin >> T;
	while(T--)	solve();
	return 0;
}