加权重随机算法

场景：有Ｎ个合作方，每一个合作方都有一定的权重，按权重随机选择一个合作方

typedef struct

{

string k;//partner_id

string v;//value

string m;//0:number 1:ratio

}Bookpartner_count_listInfo;

string GetRandNumRatio( vector<Bookpartner_count_listInfo> arpartner_count_list)

{

int weight = 0;

int user = 0;

Bookpartner_count_listInfo bp_cunt_list_temp[128];

for( vector<Bookpartner_count_listInfo>::iterator it = arpartner_count_list.begin(); it < arpartner_count_list.end(); it++)

{

weight += atoi(it->v.c_str());

for( int i = 0; i < atoi( it->v.c_str()); i++ )

{

*(bp_cunt_list_temp + weight - i) = *it;

}

}

struct timeval tv;

gettimeofday(&tv, NULL);

srand(tv.tv_usec);

user = rand() % weight;

Bookpartner_count_listInfo bk_pcl_temp = bp_cunt_list_temp[user];

return bk_pcl_temp.k;

}