Commit f1d0427

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Add C++ implementation

Signed-off-by: begeekmyfriend <begeekmyfriend@gmail.com>

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	`1`	`+#include <bits/stdc++.h>`
	`2`	`+`
	`3`	`+using namespace std;`
	`4`	`+`
	`5`	`+/**`
	`6`	`+ * Your LRUCache object will be instantiated and called as such:`
	`7`	`+ * LRUCache* obj = new LRUCache(capacity);`
	`8`	`+ * int param_1 = obj->get(key);`
	`9`	`+ * obj->put(key,value);`
	`10`	`+ */`
	`11`	`+class LRUCache {`
	`12`	`+public:`
	`13`	`+ LRUCache(int capacity) {`
	`14`	`+ capacity_ = capacity;`
	`15`	`+ }`
	`16`	`+`
	`17`	`+ int get(int key) {`
	`18`	`+ if (ht_.find(key) == ht_.end()) {`
	`19`	`+ return -1;`
	`20`	`+ }`
	`21`	`+`
	`22`	`+ int value = ht_[key]->second;`
	`23`	`+ if (li_.front().second != value) {`
	`24`	`+ li_.erase(ht_[key]);`
	`25`	`+ li_.push_front(make_pair(key, value));`
	`26`	`+ ht_[key] = li_.begin(); // iterator failure`
	`27`	`+ }`
	`28`	`+`
	`29`	`+ return value;`
	`30`	`+ }`
	`31`	`+`
	`32`	`+ void put(int key, int value) {`
	`33`	`+ if (ht_.find(key) != ht_.end()) {`
	`34`	`+ li_.erase(ht_[key]);`
	`35`	`+ } else {`
	`36`	`+ if (li_.size() == capacity_) {`
	`37`	`+ auto lru = li_.back();`
	`38`	`+ li_.pop_back();`
	`39`	`+ ht_.erase(lru.first);`
	`40`	`+ }`
	`41`	`+ }`
	`42`	`+ li_.push_front(make_pair(key, value));`
	`43`	`+ ht_[key] = li_.begin(); // iterator failure`
	`44`	`+ }`
	`45`	`+`
	`46`	`+private:`
	`47`	`+ int capacity_;`
	`48`	`+ list<pair<int, int>> li_;`
	`49`	`+ unordered_map<int, pair<int, int>::iterator> ht_;`
	`50`	`+};`

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