#include <iostream>
#include <vector>
#include <bits/stdc++.h>
#include <algorithm>
using namespace std;
const long long MOD = 1e9+7;
vector<long long> v1;
long long dp[50][32][32][5][5];
long long rec(long long len,long long a,long long b,bool limit, int leading){
// cout<<len<<" "<<a<<" "<<b<<" "<<limit<<" "<<leading<<endl;
if(dp[len][a][b][limit][leading]!=-1){
return dp[len][a][b][limit][leading];
}
if(len >= v1.size()-1){
if(len == 3){
}
return 1;
}
if(limit){
//last digit added was the largest possible digit
dp[len][a][b][limit][leading] = 0;
for(long long i=0;i<=9;i++){
if(i>v1[len+1]){
//can't add a larger digit
break;
}
if(leading == 3 && i==0){
//a new digit was just added after a bunch of zeroes
if(i==v1[len+1]){
//largest possible digit I can add(Can add a 0, leading 0s don't count as a palindrome)
dp[len][a][b][1][leading] += rec(len+1,b,i,1,0);
dp[len][a][b][1][leading]%=MOD;
}else{
//can do the same thing
dp[len][a][b][1][leading] += rec(len+1,b,i,0,0);
dp[len][a][b][1][leading]%=MOD;
}
continue;
}
else if(leading ==3){
//a number that's not 0 is being added after a number that's just been added after a bunch of 0s
if((i!=a && i!=b) && i == v1[len+1]){
//if this number's not a palindrome and it's the largest possible digit to add, add it
dp[len][a][b][1][leading] += rec(len+1,b,i,1,0);
dp[len][a][b][1][leading]%=MOD;
continue;
}
else if(i!=a && i!=b){
//same as above, but it's not the larges possible digit to add
dp[len][a][b][1][leading] += rec(len+1,b,i,0,0);
dp[len][a][b][1][leading]%=MOD;
continue;
}
}
else if(leading && i==0){
//have leading 0s, want to add another 0
if(i==v1[len+1]){
//largest digit we can add is this 0(I don't think this case would actually exist)
dp[len][a][b][1][leading] += rec(len+1,b,i,1,1);
dp[len][a][b][1][leading]%=MOD;
}else{
//we add this 0 and continue (our current string is just a bunch of 0s)
dp[len][a][b][1][leading] += rec(len+1,b,i,0,1);
dp[len][a][b][1][leading]%=MOD;
}
continue;
}
else if(leading){
//we have a bunch of leading 0s and we want to add a non zero digit
if((i!=a && i!=b) && i == v1[len+1]){
//first 2 conditions will always hold true I think,the third is a check to see if this digit is the max digit we can add. If it is we shift our leading state to 3(dealt with above)
dp[len][a][b][1][leading] += rec(len+1,b,i,1,3);
dp[len][a][b][1][leading]%=MOD;
continue;
}
else if(i!=a && i!=b){
//Again first 2 conditions will always hold true
dp[len][a][b][1][leading] += rec(len+1,b,i,0,3);
dp[len][a][b][1][leading]%=MOD;
continue;
}
}
else if((i!=a && i!=b) && i == v1[len+1]){
//after a bunch of leading 0s(or none), we have a non zero digit + x more digits (where x+1>=2)
dp[len][a][b][1][leading] += rec(len+1,b,i,1,0);
dp[len][a][b][1][leading]%=MOD;
}
else if(i!=a && i!=b){
dp[len][a][b][1][leading] += rec(len+1,b,i,0,0);
dp[len][a][b][1][leading]%=MOD;
}
}
dp[len][a][b][limit][leading]%=MOD;
return dp[len][a][b][limit][leading];
}else{
dp[len][a][b][limit][leading] = 0;
for(long long i=0;i<=9;i++){
if(leading == 3 && i == 0){
dp[len][a][b][limit][leading] += rec(len+1,b,i,limit,0);
dp[len][a][b][limit][leading]%=MOD;
}else if(leading ==3){
if(i!=a && i!=b){
dp[len][a][b][limit][leading] += rec(len+1,b,i,limit,0);
dp[len][a][b][limit][leading]%=MOD;
}
}
else if(leading && i==0){
dp[len][a][b][limit][leading] += rec(len+1,b,i,limit,1);
dp[len][a][b][limit][leading]%=MOD;
continue;
}else if(leading){
dp[len][a][b][limit][leading] += rec(len+1,b,i,limit,3);
dp[len][a][b][limit][leading]%=MOD;
continue;
}
else if(i!=a && i!=b){
dp[len][a][b][limit][leading] += rec(len+1,b,i,limit,0);
dp[len][a][b][limit][leading]%=MOD;
}
}
dp[len][a][b][limit][leading]%=MOD;
return dp[len][a][b][limit][leading];
}
}
long long solve(long long curr){
v1.clear();
for(long long i=0;i<=49;i++){
for(long long j=0;j<=31;j++){
for(long long k=0;k<=31;k++){
for(long long l=0;l<=4;l++){
for(long long m=0;m<=4;m++){
dp[i][j][k][l][m] = -1;
}
}
}
}
}
while(curr){
v1.push_back(curr%10);
curr/=10;
}
v1.push_back(0);
reverse(v1.begin(),v1.end());
long long ans = 0;
for(long long i=0;i<=9;i++){
if(v1[1]<i){
break;
}
if(i ==0){
ans+=rec(1,30,0,false,true);
ans%=MOD;
// cout<<ans<<endl;
continue;
}
ans+=rec(1,30,i,v1[1] == i,false);
ans%=MOD;
//cout<<ans<<endl;
}
return ans;
}
int main(){
long long a,b;
cin>>a>>b;
cout<<solve(b)-solve(a-1)<<endl;
}
Compilation message
numbers.cpp: In function 'long long int rec(long long int, long long int, long long int, bool, int)':
numbers.cpp:15:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if(len >= v1.size()-1){
~~~~^~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 2 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 3 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 4 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 5 |
Incorrect |
11 ms |
10360 KB |
Output isn't correct |
| 6 |
Incorrect |
12 ms |
10360 KB |
Output isn't correct |
| 7 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 8 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 9 |
Correct |
11 ms |
10360 KB |
Output is correct |
| 10 |
Correct |
11 ms |
10232 KB |
Output is correct |
| 11 |
Correct |
11 ms |
10360 KB |
Output is correct |
| 12 |
Correct |
12 ms |
10332 KB |
Output is correct |
| 13 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 14 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 15 |
Incorrect |
14 ms |
10376 KB |
Output isn't correct |
| 16 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 17 |
Correct |
11 ms |
10360 KB |
Output is correct |
| 18 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 19 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 20 |
Correct |
12 ms |
10360 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 2 |
Incorrect |
12 ms |
10352 KB |
Output isn't correct |
| 3 |
Incorrect |
12 ms |
10276 KB |
Output isn't correct |
| 4 |
Incorrect |
12 ms |
10360 KB |
Output isn't correct |
| 5 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 6 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 7 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 8 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 9 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 10 |
Correct |
11 ms |
10360 KB |
Output is correct |
| 11 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 12 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 13 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 14 |
Correct |
14 ms |
10360 KB |
Output is correct |
| 15 |
Correct |
14 ms |
10360 KB |
Output is correct |
| 16 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 17 |
Correct |
13 ms |
10360 KB |
Output is correct |
| 18 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 19 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 20 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 21 |
Incorrect |
11 ms |
10360 KB |
Output isn't correct |
| 22 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 23 |
Incorrect |
12 ms |
10360 KB |
Output isn't correct |
| 24 |
Correct |
13 ms |
10332 KB |
Output is correct |
| 25 |
Incorrect |
12 ms |
10412 KB |
Output isn't correct |
| 26 |
Incorrect |
12 ms |
10332 KB |
Output isn't correct |
| 27 |
Incorrect |
12 ms |
10360 KB |
Output isn't correct |
| 28 |
Incorrect |
14 ms |
10360 KB |
Output isn't correct |
| 29 |
Correct |
13 ms |
10360 KB |
Output is correct |
| 30 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 31 |
Incorrect |
12 ms |
10276 KB |
Output isn't correct |
| 32 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 33 |
Incorrect |
12 ms |
10360 KB |
Output isn't correct |
| 34 |
Correct |
12 ms |
10360 KB |
Output is correct |
| 35 |
Incorrect |
12 ms |
10360 KB |
Output isn't correct |
| 36 |
Incorrect |
14 ms |
10360 KB |
Output isn't correct |
| 37 |
Incorrect |
14 ms |
10360 KB |
Output isn't correct |
| 38 |
Incorrect |
13 ms |
10360 KB |
Output isn't correct |
| 39 |
Incorrect |
12 ms |
10360 KB |
Output isn't correct |
| 40 |
Correct |
12 ms |
10264 KB |
Output is correct |
| 41 |
Incorrect |
12 ms |
10360 KB |
Output isn't correct |
| 42 |
Correct |
14 ms |
10364 KB |
Output is correct |
| 43 |
Incorrect |
12 ms |
10360 KB |
Output isn't correct |
| 44 |
Incorrect |
13 ms |
10360 KB |
Output isn't correct |
| 45 |
Incorrect |
12 ms |
10360 KB |
Output isn't correct |
