LRU Cache LeetCode solution in Python

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class LRUCache {
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    int N;
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    list<int> pages;
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    unordered_map<int, pair<int, list<int>::iterator>> cache;
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public:
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    LRUCache(int capacity) : N(capacity) {
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    }
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    int get(int key) {
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        if (cache.find(key) != cache.end()) {
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            pages.erase(cache[key].second);
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            pages.push_front(key);
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            cache[key].second = pages.begin();
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            return cache[key].first;
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        }
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        return -1;
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    }
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    void put(int key, int value) {
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        if (cache.find(key) != cache.end()) {
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            pages.erase(cache[key].second);
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        } else {
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            if (pages.size() == N) {
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                int lru = pages.back();
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                cache.erase(lru);
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                pages.pop_back();
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            }
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        }
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        pages.push_front(key);
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        cache[key] = {value, pages.begin()};
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    }
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};