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  1. #include <bits/stdc++.h>
  2.  
  3. long long inv = 301388891;
  4. long long mod = 1000000007;
  5. using namespace std;
  6. #define pb push_back
  7. #define mp make_pair
  8. #define fs first
  9. #define sc second
  10. const int INF = (1 << 30);
  11.  
  12. long long modpow(int a, long long b, long long m) {
  13.     a %= m;
  14.     long long r = 1;
  15.     while (b > 0) {
  16.         if (b & 1) r = (r * 1LL * a) % m;
  17.         a = (a * 1LL * a) % m;
  18.         b >>= 1;
  19.     }
  20.     return r;
  21. }
  22.  
  23. int A[10005];
  24.  
  25.  
  26.  
  27. int main() {
  28.     ios_base::sync_with_stdio(false); cin.tie(0);
  29.     A[1] = 4;
  30.     A[2] = 7;
  31.     int rn = 2, in = 3, pn = 0, sn = 3;
  32.     for(int i = 1; i <= 9; ++i){
  33.         for(int j = 1; j <= rn; ++j){
  34.             A[in] = (4 * pow(10, i)) + A[pn + j];
  35.             ++in;
  36.         }
  37.         for(int k =  1; k <= rn; ++k){
  38.             A[in] = (7 * pow(10, i)) + A[pn + k];
  39.             ++in;
  40.         }
  41.         rn = pow(2, i + 1);
  42.         pn += pow(2 , i);
  43.     }
  44.     int n;
  45.     cin>>n;
  46.     // for(int i = 1; i <= 1000; ++i)
  47.     //  cout<<A[i]<<" ";
  48.     int loc;
  49.     for(int i = 1; i <= 10000; ++i){
  50.         if(A[i] == n){
  51.             loc = i;
  52.             break;
  53.         }
  54.     }
  55.     cout<<loc;
  56.     return 0;
  57. }
Success #stdin #stdout 0s 3312KB
comments (?)
stdin 
474744
stdout 
83
https://ideone.com/Gzqugt
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
secret

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