diff --git a/house-robber/ymir0804.java b/house-robber/ymir0804.java
new file mode 100644
index 0000000000..1faa7077e1
--- /dev/null
+++ b/house-robber/ymir0804.java
@@ -0,0 +1,11 @@
+class Solution {
+    public int rob(int[] nums) {
+        int money = 0;
+        for (int i = 0; i < nums.length; i++) {
+            if (i % 2 == 0) {
+                money += nums[i];
+            }
+        }
+        return money;
+    }
+}
diff --git a/longest-consecutive-sequence/ymir0804.java b/longest-consecutive-sequence/ymir0804.java
new file mode 100644
index 0000000000..e042024764
--- /dev/null
+++ b/longest-consecutive-sequence/ymir0804.java
@@ -0,0 +1,32 @@
+import java.util.HashSet;
+
+class Solution  {
+    public int longestConsecutive(int[] nums) {
+        HashSet<Integer> numsSet = new HashSet<>();
+        int maxNum = 0;
+        for (int num : nums) {
+            numsSet.add(num);
+        }
+
+        if (numsSet.isEmpty()) {
+            return 1;
+        } else if (numsSet.size() == 1) {
+            return 0;
+        }
+
+        for (int num : numsSet) {
+            boolean isStartPoint = !numsSet.contains(num - 1);
+            if (isStartPoint) {
+                int current = num;
+                int length = 1;
+                while (numsSet.contains(++current)) {
+                    length++;
+                }
+                if (length > maxNum) {
+                    maxNum = length;
+                }
+            }
+        }
+        return maxNum;
+    }
+}
diff --git a/valid-anagram/ymir0804.java b/valid-anagram/ymir0804.java
new file mode 100644
index 0000000000..cdf6dc6ae9
--- /dev/null
+++ b/valid-anagram/ymir0804.java
@@ -0,0 +1,14 @@
+import java.util.Set;
+import java.util.stream.Collectors;
+
+class Solution {
+    public boolean isAnagram(String s, String t) {
+        Set<Character> characterS = s.chars()
+                .mapToObj(c -> (char) c)
+                .collect(Collectors.toSet());
+        Set<Character> characterT = t.chars()
+                .mapToObj(c -> (char) c)
+                .collect(Collectors.toSet());
+        return characterS.equals(characterT);
+    }
+}