uva 11205 The broken pedometer

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dfs递归枚举所有的子集，检验每一个子集是否能够使得每一个数字的编码不同，如果发现这样的子集，就统计其中1的个数，将结果更新为当前结果和前面统计出的1的个数的较小值，递归枚举结束后，得到的全局变量result就是最后的结果。

#include <stdio.h>#include <math.h>#include <vector>#include <set>using namespace std;vector<int> original_code;int arr[16];int result;void dfs(int len, int cur){if(cur == len){int mask, i, j, new_code;set<int> last_code;int one_count;mask = 0;for(i=0; i<len; i++){if(arr[i])mask += (int)pow(2.0, i);}last_code.clear();for(i=0; i<original_code.size(); i++){new_code = mask&original_code[i];if(last_code.find(new_code) != last_code.end())break;elselast_code.insert(new_code);}if(i == original_code.size()){//统计1的个数one_count = 0;for(j=0; j<len; j++)if(arr[j])one_count++;if(one_count < result)result = one_count;}return;}arr[cur] = 0;dfs(len, cur+1);arr[cur] = 1;dfs(len, cur+1);}void func(int m, int n){double r;//递归生成子集result = m;dfs(m, 0);printf("%d\n", result);}int main(void){int m, n;int data, sum;int i, j;int N;//freopen("input.dat", "r", stdin);scanf("%d", &N);while(N--){scanf("%d %d", &m, &n);original_code.clear();for(i=1; i<=n; i++){sum = 0;for(j=0; j<m; j++){scanf("%d", &data);if(data) sum += (int)pow(2.0, j);}original_code.push_back(sum);}func(m, n);}return 0;}