c++怎么写simhash

Simhash的C++实现可以参考以下代码：

#include <iostream>
#include <string>
#include <vector>
#include <sstream>
#include <bitset>

using namespace std;

bitset<64> simhash(const string& input, const vector<string>& tokens, const vector<int>& weights)
{
    vector<int> shingles(tokens.size());

    for (int i = 0; i < tokens.size(); ++i)
    {
        unsigned int hash = 0;
        for (int j = 0; j < tokens[i].size(); ++j)
        {
            hash = 65599 * hash + tolower(tokens[i][j]);
        }
        shingles[i] = hash;
    }

    vector<int> v(64, 0);
    for (int i = 0; i < shingles.size(); ++i)
    {
        for (int j = 0; j < 64; ++j)
        {
            if (shingles[i] & (1ull << j))
            {
                v[j] += weights[i];
            }
            else
            {
                v[j] -= weights[i];
            }
        }
    }

    bitset<64> result;
    for (int i = 0; i < 64; ++i)
    {
        if (v[i] >= 0)
        {
            result.set(i, 1);
        }
    }

    return result;
}

int main()
{
    string input = "simhash is a hash function used for detecting near-duplicate documents among a large set of documents";

    stringstream ss(input);
    vector<string> tokens;
    string token;
    while (getline(ss, token, ' '))
    {
        tokens.push_back(token);
    }

    vector<int> weights(tokens.size(), 1);
    bitset<64> sh = simhash(input, tokens, weights);

    cout << sh << endl;
    return 0;
}

这段代码实现了对一个字符串输入进行Simhash计算的过程，其中需要输入一个token列表和对应的weights列表，这里暂时默认使用所有token的权重都为1。最终输出一个64位的二进制表示的simhash值。