C++ 创建unordered_map将vector作为key

unordered_map<vector<int>,int> hashtable;

自定义哈希函数

// cited from: 
// https://stackoverflow.com/questions/20511347/a-good-hash-function-for-a-vector
// equivalent to : hash_combine() (from boost lib)
struct HashFunc_t
{
	size_t operator() (const vector<int>& key) const {
		std::hash<int> hasher;
		size_t seed = 0;
		for (int i : key) {
			seed ^= hasher(i) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
		}
		return seed;
	}
};

自定义等价操作函数（可选）

struct Equalfunc_t {
	bool operator() (vector<int> const& a, vector<int> const& b) const {
		for (int i = 0; i < a.size(); i++)
		{
			if (a[i] != b[i])
				return 0;
		}
		return 1;
	}
};