#include <bits/stdc++.h>
using namespace std;
bool *Seive(long long n, bool *p) {
  memset(p, 1, sizeof(p));
  long long i, j;
  for (i = 2; i <= n; i++) {
    if (p[i] == 1)
      for (j = i * i; j <= n; j += i) {
        p[j] = 0;
      }
  }
  p[1] = 0;
  return p;
}
long long gcd(long long a, long long b) {
  if (b == 0)
    return a;
  else
    return gcd(b, a % b);
}
long long modexp(long long x, long long y) {
  if (y == 0)
    return 1;
  else if (y % 2 == 0) {
    return modexp((x * x) % (long long)(1e9 + 7), y / 2);
  } else {
    return (x * modexp((x * x) % (long long)(1e9 + 7), (y - 1) / 2)) %
           (long long)(1e9 + 7);
  }
}
long long fact(long long n) {
  long long f = 1;
  for (long long i = 2; i <= n; i++) {
    f = (i % (long long)(1e9 + 7) * f % (long long)(1e9 + 7)) %
        (long long)(1e9 + 7);
  }
  return f;
}
long long nCr(long long n, long long r) {
  return (fact(n) * modexp((fact(n - r) * fact(r)) % (long long)(1e9 + 7),
                           (long long)(1e9 + 7) - 2)) %
         (long long)(1e9 + 7);
}
void showlist(list<int64_t> g) {
  list<int64_t>::iterator it;
  for (it = g.begin(); it != g.end(); ++it) cout << *it << " ";
  cout << '\n';
}
void swap(int64_t &a, int64_t &b) {
  int64_t t;
  t = a;
  a = b;
  b = t;
}
void build(int64_t l, int64_t r, int64_t i) {
  if (l == r) {
  } else {
    int64_t mid = (l + r) / 2;
    build(l, mid, 2 * i);
    build(mid + 1, r, 2 * i + 1);
  }
}
void update(int64_t p, int64_t l, int64_t r, int64_t i) {
  if (l == r) {
  } else {
    int64_t mid = (l + r) / 2;
    if (p <= mid) {
      update(p, l, mid, 2 * i);
    } else {
      update(p, mid + 1, r, 2 * i + 1);
    }
  }
}
void query(int64_t y, int64_t z, int64_t l, int64_t r, int64_t i) {
  if (y <= l && z >= r) {
  } else {
    int64_t mid = (l + r) / 2;
    if (z <= mid) {
      query(y, z, l, mid, 2 * i);
    } else if (y > mid) {
      query(y, z, mid + 1, r, 2 * i + 1);
    } else {
      query(y, z, l, mid, 2 * i);
      query(y, z, mid + 1, r, 2 * i + 1);
    }
  }
}
void make_set(int64_t v) {}
int64_t find_set(int64_t v) {}
void union_sets(int64_t a, int64_t b) {}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int64_t T, hh = 0;
  cin >> T;
  while (T--) {
    int64_t n, i, j, k;
    cin >> n;
    vector<vector<int64_t>> a(10000);
    int64_t x;
    for (i = 0; i < n; i++) {
      cin >> x;
      a[x].push_back(i);
    }
    int64_t v[n];
    int64_t c = 0;
    for (i = 0; i < 10000; i += 10) {
      vector<int64_t> ex;
      vector<int64_t> r;
      for (j = 0; j < 10; j++) {
        if (a[i + j].size() >= 1) {
          v[a[i + j][0]] = i + j;
        }
        if (a[i + j].size() > 1) {
          for (k = 1; k < a[i + j].size(); k++) {
            ex.push_back(a[i + j][k]);
          }
        }
        if (a[i + j].size() == 0) {
          r.push_back(i + j);
        }
      }
      c += ex.size();
      for (j = 0; j < ex.size(); j++) {
        v[ex[j]] = r[j];
      }
    }
    cout << c << "\n";
    for (i = 0; i < n; i++) {
      int64_t g[4];
      j = 3;
      while (j >= 0) {
        g[j] = v[i] % 10;
        v[i] = v[i] / 10;
        j--;
      }
      for (j = 0; j < 4; j++) cout << g[j];
      cout << "\n";
    }
  }
  return 0;
}
