[leebeanbin] WEEK 01 Solution

contains-duplicate/leebeanbin.java

@@ -0,0 +1,18 @@
+import java.util.HashSet;
+
+class Solution {
+	public boolean containsDuplicate(int[] nums) {
+		HashSet<Integer> arr = new HashSet<Integer>();
+		boolean answer = false;
+
+		for(int num : nums){
+			arr.add(num);
+		}
+
+		if(nums.length != arr.size()){
+			answer = true;
+		}
+
+		return answer;
+	}
+}

two-sum/leebeanbin.java

@@ -0,0 +1,28 @@
+import java.util.HashMap;
+
+public class leebeanbin {
+	public static int[] bruteForce(int[] nums, int target) {
+		for (int i = 0; i < nums.length; i++) {
+			for (int j = i + 1; j < nums.length; j++) {
+				if (nums[i] + nums[j] == target) {
+					return new int[]{i, j};
+				}
+			}
+		}
+		return null;
+	}
+
+	public static int[] hashMap(int[] nums, int target) {
+		HashMap<Integer, Integer> arr = new HashMap<>();
+
+		for (int i = 0; i < nums.length; i++) {
+			arr.put(nums[i], i);
+
+			if (arr.containsKey(target - nums[i])) {
+				return new int[]{arr.get(target - nums[i]), i};
+			}
+		}
+
+		return null;
+	}
+}