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  1. /*Author : Siriuslight | Subham Pal
  2.            Army Institute of Technology
  3. */
  4. #include<bits/stdc++.h>
  5. #define FIO ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0);
  6. #define sd(x) scanf("%d", &x);
  7. #define sld(x) scanf("%lld", &x);
  8. using namespace std;    typedef long long ll;    typedef long double ld;
  9. const ll inf = 1e9, N = 1e5+5;
  10. const ll INF = 1e18, MOD = 1e9+7;
  11. ll powmod(ll a,ll b,ll m=MOD){ll r=1;while(b>0){if(b&1)r=r*a%m;a=a*a%m;b>>=1;}return r;}
  12. ll power(ll a,ll b){ll r=1;while(b>0){if(b&1)r=r*a;a=a*a;b>>=1;}return r;}
  13. ll gcd(ll a,ll b){if(b>a)swap(a,b);if(!b)return a;return gcd(b,a%b);}
  14.  
  15. int ans(0);
  16.  
  17. bool palin(vector<int> v){
  18.     for(int i = 0; i < v.size() / 2; ++i)
  19.         if(v[i] != v[v.size() - 1 - i])
  20.             return 0;
  21.     return 1;
  22. }
  23.  
  24. vector <int> add(vector <int> v1){
  25.     vector <int> v2, res;
  26.     v2 = v1;
  27.     reverse(v2.begin(), v2.end());
  28.     int carry(0);
  29.     for(int i = v1.size() - 1; i >= 0; --i){
  30.         int t = v1[i] + v2[i] + carry;
  31.         res.push_back(t % 10);
  32.         carry = t / 10;
  33.     }
  34.     while(carry){
  35.         res.push_back(carry % 10);
  36.         carry /= 10;
  37.     }
  38.     reverse(res.begin(), res.end());
  39.     return res;
  40. }
  41.  
  42. bool lychrel(int x){
  43.     vector <int> v;
  44.     while(x){
  45.         v.push_back(x % 10);
  46.         x /= 10;
  47.     }
  48.     reverse(v.begin(), v.end());
  49.     for(int i = 0; i <= 50; ++i){
  50.         if(palin(v)){
  51.             return 0;
  52.         }
  53.         v = add(v);
  54.     }
  55.     return 1;
  56. }
  57.  
  58. int main(){
  59.     FIO;
  60.     cout << setprecision(10) << fixed;
  61.  
  62.     for(int i = 1; i < 1e4; ++i){
  63.         ans += lychrel(i);
  64.     }
  65.     cout << ans;
  66.     return 0;
  67. }
Success #stdin #stdout 0.03s 4356KB
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https://ideone.com/4ZAiiP
language:
C++14 (gcc 8.3)
created:
5 years ago
visibility:
secret

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