DigitDp Format

#include <bits/stdc++.h>

using namespace std;

#define int long long

int res, m, ans;

int f(int pos, int Small, int ok, vector<int>&v, vector<vector<vector<int>>>&dp) {
  if (pos == m)return ok;
  if (dp[pos][Small][ok] != -1)return dp[pos][Small][ok];
  int l = 0, r = v[pos], val = 0;
  if (Small)r = 9;
  for (int j = l; j <= r; j++) {
    val += f(pos + 1, Small | (j < r), ok | (j == 7), v, dp);
  }
  return dp[pos][Small][ok] = val;
}

void solve() {

  int n;
  cin >> n;
  int s = n;

  vector<int>v;
  while (s) {
    v.push_back(s % 10);
    s /= 10;
  }
  m = v.size();
  reverse(v.begin(), v.end());

  vector<vector<vector<int>>>dp(11, vector<vector<int>>(2, vector<int>(2, -1)));

  ans += n;
  res += f(0, 0, 0, v, dp);

}

signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0); cout.tie(0);

  int t;
  cin >> t;

  while (t--) {

    solve();

  }

  cout << ans - res << '\n';

  return 0;
}