#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; } |
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