Bounded LRU cache on std::list plus hash map

#include <list>
#include <unordered_map>
#include <utility>

struct LruCache {
    explicit LruCache(std::size_t cap) : cap(cap) {}
    int* find(int k) {
        auto it = map.find(k);
        if (it == map.end()) return nullptr;
        order.splice(order.begin(), order, it->second);
        return &it->second->second;
    }
    void put(int k, int v) {
        if (int* p = find(k)) { *p = v; return; }
        if (map.size() == cap) { map.erase(order.back().first); order.pop_back(); }
        order.emplace_front(k, v);
        map[k] = order.begin();
    }
    std::size_t cap;
    std::list<std::pair<int, int>> order;
    std::unordered_map<int, std::list<std::pair<int, int>>::iterator> map;
};