The 2018 ACM-ICPC Asia Qingdao Regional Contest M. Function and Function(规律)

#include <bits/stdc++.h>
#define ll long long
using namespace std;
int T,n,k,ans;
map<int,int> ma;

void init(){
  ma[0] = 1;
  ma[1] = 0;
  ma[2] = 0;
  ma[3] = 0;
  ma[4] = 1;
  ma[5] = 0;
  ma[6] = 1;
  ma[7] = 0;
  ma[8] = 2;
  ma[9] = 1;
}

int Fun(int x){
  int sum = 0;
  while(x){
    sum += ma[x % 10];
    x /= 10;
  }
  return sum;
}

int main()
{
  init();
  scanf("%d",&T);
  while(T--){
    scanf("%d%d",&n,&k);
    while(n >= 2 && k){
      n = Fun(n);
      k--;
    }
    if(k & 1) n ^= 1;
    printf("%d\n",n);
  }
  return 0;
}