#include <bits/stdc++.h> using namespace std; int64_t n; int64_t digits; int64_t countDigits(int64_t x){ if(x == 0){ return 1; } int res = 0; while(x > 0){ x /= 10; res++; } return res; } int64_t max(int a, int64_t b){ return max((int64_t)a, b); } int64_t max(int64_t a, int b){ return max(b, a); } int main(void){ ios_base::sync_with_stdio(0); cin.tie(0); cin >> n; digits = countDigits(n); int64_t dp[digits + 1]; dp[0] = n % 10 + 1; if(digits == 1){ cout << dp[0]; return 0; } int64_t dig1 = (n / 10) % 10; int64_t num1 = n % 100; dp[1] = dp[0] * (dig1 + 1); if(num1 >= 10 and num1 <= 18){ dp[1] += 19 - num1; } if(digits == 2){ cout << dp[1]; return 0; } n /= 10; for(int64_t i = 2; i < digits; i++){ dig1 = (n / 10) % 10; num1 = n % 100; int64_t a = 0; if(num1 >= 10 and num1 <= 18){ a = 19 - num1; } int64_t b = dig1 + 1; dp[i] = a * dp[i - 2] + b * dp[i - 1]; n /= 10; } cout << dp[digits - 1]; return 0; }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 | #include <bits/stdc++.h> using namespace std; int64_t n; int64_t digits; int64_t countDigits(int64_t x){ if(x == 0){ return 1; } int res = 0; while(x > 0){ x /= 10; res++; } return res; } int64_t max(int a, int64_t b){ return max((int64_t)a, b); } int64_t max(int64_t a, int b){ return max(b, a); } int main(void){ ios_base::sync_with_stdio(0); cin.tie(0); cin >> n; digits = countDigits(n); int64_t dp[digits + 1]; dp[0] = n % 10 + 1; if(digits == 1){ cout << dp[0]; return 0; } int64_t dig1 = (n / 10) % 10; int64_t num1 = n % 100; dp[1] = dp[0] * (dig1 + 1); if(num1 >= 10 and num1 <= 18){ dp[1] += 19 - num1; } if(digits == 2){ cout << dp[1]; return 0; } n /= 10; for(int64_t i = 2; i < digits; i++){ dig1 = (n / 10) % 10; num1 = n % 100; int64_t a = 0; if(num1 >= 10 and num1 <= 18){ a = 19 - num1; } int64_t b = dig1 + 1; dp[i] = a * dp[i - 2] + b * dp[i - 1]; n /= 10; } cout << dp[digits - 1]; return 0; } |