uva729

Description

The Hamming Distance Problem

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Thinking

枚举排列问题，从左到右递归处理。

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Answer

#include <iostream>
using namespace std;
int ds;
int N, H;
int count(int* A, int num, int cur){
    int count = 0;
    for (int i = 0; i < cur; ++i) {
        if (A[i] == num)
            count++;
    }
    return count;
}
void print_permutation(int* A, int cur){
    if (cur == N){
        for (int i = 0; i < N; ++i)
            cout << A[i];
        cout << endl;
    }
    else{
        for (int bit = 0; bit <= 1; ++bit) {
            // 若在前面出现的次数符合要求
            int ok = (count(A, bit, cur) < (bit == 1 ? H : N-H) ? 1 : 0);
            if (ok){
                A[cur] = bit;
                print_permutation(A, cur+1);
            }
        }
    }
}
int main(){
    cin >> ds;
    while(ds--){
        cin >> N >> H;
        int A[N] = {0};
        print_permutation(A, 0);
        if (ds) cout << endl;
    }
}