{%hackmd theme-dark %}

# Grafos II - Upsolving

###### tags: `upsolving` `ps2020` `grafo`

## C

#define pb push_back;
#define all(x) x.begin(), x.end()

bool prime[N] = {true};

void Sieve(int n){
    for(int i = 2; i < n)
}


string digits(int v) {
  string s;
  while(v) {
    s.pb(v%10 + '0');
    v /= 10;
  }
  reverse(s.begin(), s.end());
  return s;
}

int toint(string s) {
  int ans = 0;
  for(char c: s) {
    ans *= 10;
    ans += c - '0';
  }
  return ans;
}

void contruct(int v) {
  string s = digits(v);
  for(int i = 0; i < 4; i++) {
    for(int j = 0; j <= 9; j++) if(j+'0' != s[i]){
      string a = s;
      s[i] = j+'0';
      int tmp = toint(v);
      
      if(prime[tmp]) adj[v].pb(tmp);
     
  }
 


int main() {
  
  {
  }