algorithm001
diff --git a/Week_04/id_135/LeetCode_169_135.java b/Week_04/id_135/LeetCode_169_135.java
@@ -0,0 +1,17 @@
+class Solution {
+   public int majorityElement(int[] nums) {
+		int count = 1;
+		int maj = nums[0];
+		for (int i = 1; i < nums.length; i++) {
+			if (maj == nums[i])
+				count++;
+			else {
+				count--;
+				if (count == 0) {
+					maj = nums[i + 1];
+				}
+			}
+		}
+		return maj;
+   }
+}
diff --git a/Week_04/id_135/LeetCode_720_135.java b/Week_04/id_135/LeetCode_720_135.java
@@ -0,0 +1,16 @@
+class Solution {
+    public String longestWord(String[] words) {
+        Arrays.sort(words);
+
+    Set<String> set = new HashSet<>();
+    String res = "";
+    for (String s : words) {
+        //如果单词只有一个字母，那一定是共有的
+        if (s.length() == 1 || set.contains(s.substring(0, s.length() - 1))) {
+            res = s.length() > res.length() ? s : res;
+            set.add(s);
+        }
+    }
+    return res;
+    }
+}