93 lines
2.6 KiB
C++
93 lines
2.6 KiB
C++
#include <string>
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#include <vector>
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#include <map>
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#include <unordered_map>
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#include <unordered_set>
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#include <iostream>
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/**
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* 432. All O`one Data Structure
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* Design a data structure to store the strings' count with the ability to return the strings with minimum and maximum counts.
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* Implement the AllOne class:
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* - AllOne() Initializes the object of the data structure.
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* - inc(String key) Increments the count of the string key by 1. If key does not exist in the data structure, insert it with count 1.
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* - dec(String key) Decrements the count of the string key by 1. If the count of key is 0 after the decrement, remove it from the data structure. It is guaranteed that key exists in the data structure before the decrement.
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* - getMaxKey() Returns one of the keys with the maximal count. If no element exists, return an empty string "".
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* - getMinKey() Returns one of the keys with the minimum count. If no element exists, return an empty string "".
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*/
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class AllOne {
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private:
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int n = 0;
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std::unordered_map<int, std::string> id2Str;
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std::unordered_map<std::string, int> str2Id;
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std::map<int, std::unordered_set<int>> val2Id;
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std::unordered_map<int, int> id2Val;
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public:
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AllOne() = default;
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void inc(const std::string& key) {
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if (str2Id.count(key)) {
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int idx = str2Id[key];
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int& val = id2Val[idx];
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if (val2Id[val].size() == 1) {
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val2Id.erase(val);
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} else {
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val2Id[val].erase(idx);
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}
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val2Id[++val].insert(idx);
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} else {
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int x = str2Id[key] = ++n;
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id2Str[x] = key;
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id2Val[x] = 1;
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val2Id[1].insert(x);
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}
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}
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void dec(const std::string& key) {
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int idx = str2Id[key];
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int& val = id2Val[idx];
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if (val == 1) {
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id2Str.erase(idx);
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if (val2Id[1].size() == 1)
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val2Id.erase(1);
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else
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val2Id[1].erase(idx);
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str2Id.erase(key);
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id2Val.erase(idx);
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} else {
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if (val2Id[val].size() == 1) {
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val2Id.erase(val);
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} else {
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val2Id[val].erase(idx);
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}
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val2Id[--val].insert(idx);
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}
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}
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std::string getMaxKey() {
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return str2Id.empty() ? "" : id2Str[*(val2Id.rbegin()->second.begin())];
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}
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std::string getMinKey() {
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return str2Id.empty() ? "" : id2Str[*(val2Id.begin()->second.begin())];
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}
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};
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int main() {
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AllOne test;
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test.inc("hello");
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test.inc("hello");
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std::cout << test.getMaxKey() << std::endl;
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std::cout << test.getMinKey() << std::endl;
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test.inc("123");
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std::cout << test.getMaxKey() << std::endl;
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std::cout << test.getMinKey() << std::endl;
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test.dec("hello");
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std::cout << test.getMaxKey() << std::endl;
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std::cout << test.getMinKey() << std::endl;
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test.dec("hello");
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std::cout << test.getMaxKey() << std::endl;
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std::cout << test.getMinKey() << std::endl;
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}
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