codeforces 467B
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.
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.
Print a single integer — the number of Fedor's potential friends.
7 3 1
8
5
111
17
0
3 3 3
1
2
3
4
3
http://codeforces.com/problemset/problem/467/B
#include<iostream> #define MAX 1010 using namespace std; int soldier[MAX]; int bitcount(int x) { return x == 0 ? 0 : bitcount(x >> 1) + (x & 1); } int main() { int n, m, k; int sum = 0; cin >> n >> m >> k; for (int i = 0;i < m + 1;i++) cin >> soldier[i]; for (int i = 0;i < m;i++) { if (bitcount(soldier[i] ^ soldier[m]) <= k) sum++; } cout << sum << endl; return 0; }