#include <bits/stdc++.h> using namespace std; #define fi first #define se second #define ll long long template <class T> bool ckmax(T &a, T b) { return a < b ? (a = b, true) : false; } template <class T> bool ckmin(T &a, T b) { return a > b ? (a = b, true) : false; } int d[20]; ll dp[20][11][11][2]; ll solve(int pos, int tight, int l1, int l2, bool start) { if (pos < 0) return 1; if (!tight && dp[pos][l1][l2][start] != -1) return dp[pos][l1][l2][start]; ll res = 0; int lim = tight ? d[pos] : 9; for (int i = 0; i <= lim; i++) { if (i != l1 && i != l2) { bool nx = start || i > 0; res += solve(pos - 1, tight && i == lim, (nx ? l2 : 10), (nx ? i : 10), nx); } } if (!tight) dp[pos][l1][l2][start] = res; return res; } ll calc(ll x) { if (x < 0) return 0; int n = 0; d[0] = 0; while (x) { d[n++] = x % 10; x /= 10; } return solve(n - 1, 1, 10, 10, 0); } int main() { #define NAME "test" if (fopen(NAME".inp", "r")) { freopen(NAME".inp", "r", stdin); freopen(NAME".out", "w", stdout); } ios_base::sync_with_stdio(false); cin.tie(nullptr); memset(dp, -1, sizeof dp); ll l, r; cin >> l >> r; cout << calc(r) - calc(l - 1) << '\n'; return 0; }

numbers.cpp: In function 'int main()':
numbers.cpp:44:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |         freopen(NAME".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
numbers.cpp:45:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   45 |         freopen(NAME".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~