[crumbs22] WEEK 1

contains-duplicate/crumbs22.cpp

@@ -0,0 +1,13 @@
+#include <iostream>
+#include <vector>
+#include <unordered_set>
+
+using namespace std;
+
+class Solution {
+public:
+    bool containsDuplicate(vector<int>& nums) {
+		unordered_set<int> uset(nums.begin(), nums.end());
+		return (nums.size() != uset.size());
+    }
+};

top-k-frequent-elements/crumbs22.cpp

@@ -0,0 +1,29 @@
+bool cmp(const pair<int, int>& a, const pair<int, int>& b)
+{
+	if (a.second == b.second)
+		return a.first < b.first;
+	return a.second > b.second;
+}
+
+class Solution {
+public:
+    vector<int> topKFrequent(vector<int>& nums, int k) {
+        unordered_map<int, int> umap;
+
+		for (int i = 0; i < nums.size(); i++)
+		{
+			auto tmp = umap.find(nums[i]);
+			if (tmp != umap.end())
+				tmp->second += 1;
+			else
+				umap.insert(make_pair(nums[i], 1));
+		}
+		vector<pair<int,int>> vec(umap.begin(), umap.end()); // map을 vector로 이동
+		sort(vec.begin(), vec.end(), cmp);
+
+		vector<int> result;
+		for (int i = 0; i < k; i++)
+			result.push_back(vec[i].first);
+		return (result);
+    }
+};

two-sum/crumbs22.cpp

@@ -0,0 +1,26 @@
+#include <iostream>
+#include <vector>
+#include <algorithm>
+
+using namespace std;
+
+class Solution {
+public:
+    vector<int> twoSum(vector<int>& nums, int target) {
+		if (nums.size() == 2)
+			return {1, 2};
+		int tmp;
+		for (int i = 0; i < nums.size(); i++)
+		{
+			tmp = target - nums[i];
+			for (int j = i + 1; j < nums.size(); j++)
+			{
+				if (nums[j] == tmp)
+				{
+					return {i, j};
+				}
+			}
+		}
+		return {-1};
+    }
+};