Description
After you had helped George and Alex to move in the dorm, they went to help their friend Fedor play a new computer game «Call of Soldiers 3».
The game has (m + 1) players and n types of soldiers in total. Players «Call of Soldiers 3» are numbered form 1 to (m + 1). Types of soldiers are numbered from 0 to n - 1. Each player has an army. Army of the i-th player can be described by non-negative integer xi. Consider binary representation of xi: if the j-th bit of number xi equal to one, then the army of the i-th player has soldiers of the j-th type.
Fedor is the (m + 1)-th player of the game. He assume that two players can become friends if their armies differ in at most k types of soldiers (in other words, binary representations of the corresponding numbers differ in at most k bits). Help Fedor and count how many players can become his friends.
Input
The first line contains three integers n, m, k(1 ≤ k ≤ n ≤ 20; 1 ≤ m ≤ 1000).
The i-th of the next (m + 1) lines contains a single integer xi(1 ≤ xi ≤ 2n - 1), that describes the i-th player's army. We remind you that Fedor is the (m + 1)-th player.
Output
Print a single integer — the number of Fedor's potential friends.
Sample Input
7 3 1 8 5 111 17
0
3 3 3 1 2 3 4
3
x&(1<<j) 表示数a二进制的第j位是什么
<pre name="code" class="cpp">(x[i]&(1<<j))^(x[m+1]&(1<<j)) 异或比较两数2进制的第j位,相同为0,相异为1
#include<stdio.h>
#include<algorithm>
using namespace std;
int main(){
int n,m,k,x[1010],i,ans,j;
ans=0;
scanf("%d%d%d",&n,&m,&k);
for(i=1;i<=m+1;i++){
scanf("%d",&x[i]);
}
for(i=1;i<=m;i++){
int temp=0;
for(j=0;j<n;j++){
if((x[i]&(1<<j))^(x[m+1]&(1<<j))){
temp++;
}
}
if(temp<=k){
ans++;
}
}
printf("%d\n",ans);
return 0;
}