diff --git a/src/main/java/contest/y2023/Week354.java b/src/main/java/contest/y2023/Week354.java
new file mode 100644
index 0000000..d032539
--- /dev/null
+++ b/src/main/java/contest/y2023/Week354.java
@@ -0,0 +1,123 @@
+package contest.y2023;
+
+import java.lang.reflect.Array;
+import java.util.*;
+
+public class Week354 {
+    public static void main(String[] args) {
+        String word = "cbaaaabc";
+        List<String> forbidden = Arrays.asList("aaa", "cb");
+        System.out.println(longestValidSubstring(word, forbidden));
+    }
+
+    static List<String> strs = new ArrayList<>();
+
+    public static int longestValidSubstring(String word, List<String> forbidden) {
+        Comparator<String> lengthComparator = Comparator.comparingInt(String::length);
+        forbidden.sort(lengthComparator);
+        for (int i = 0; i < forbidden.size(); i++) {
+            for (int j = i + 1; j < forbidden.size(); j++) {
+                if(forbidden.get(j).contains(forbidden.get(i))){
+                    forbidden.remove(forbidden.get(j));
+                }
+            }
+        }
+
+        int max = getMax(word, forbidden);
+        strs.sort(lengthComparator);
+        while (strs.size() > 0 && strs.get(strs.size() - 1).length() > max) {
+            String str = strs.get(strs.size() - 1);
+            strs.remove(str);
+            max = Math.max(max, getMax(str, forbidden));
+            strs.sort(lengthComparator);
+        }
+        return max;
+    }
+
+    private static int getMax(String word, List<String> forbidden) {
+        for (String str : forbidden) {
+            if (word.contains(str)) {
+                int index = word.indexOf(str);
+                if (!strs.contains(word.substring(0, index))) {
+                    strs.add(word.substring(0, index));
+                }
+                if (!strs.contains(word.substring(index + 1))) {
+                    strs.add(word.substring(index + 1));
+                }
+                String substring = word.substring(0, index + str.length() - 1);
+                if (!strs.contains(substring)) {
+                    strs.add(substring);
+                }
+                String substring1 = word.substring(index + str.length());
+                if (!strs.contains(substring1)) {
+                    strs.add(substring1);
+                }
+                return 0;
+            }
+        }
+        return word.length();
+    }
+
+    public int minimumIndex(List<Integer> nums) {
+        int[] arr = new int[nums.size()];
+        for (int i = 0; i < nums.size(); i++) {
+            arr[i] = nums.get(i);
+        }
+        Arrays.sort(arr);
+        int cnt = 1;
+        int num = arr[0];
+        int max = 0;
+        for (int i = 1; i < nums.size(); i++) {
+            if (arr[i] == arr[i - 1]) {
+                cnt++;
+            } else {
+                if (max < cnt) {
+                    max = cnt;
+                    num = arr[i - 1];
+                }
+                cnt = 1;
+            }
+        }
+        if (max < cnt) {
+            max = cnt;
+            num = arr[nums.size() - 1];
+        }
+        if (cnt * 2 == nums.size() + 1) {
+            return -1;
+        }
+        cnt = 0;
+        for (int i = 0; i < nums.size(); i++) {
+            if (nums.get(i) == num) {
+                cnt++;
+                if (cnt * 2 > i + 1 && (max - cnt) * 2 > nums.size() - i - 1) {
+                    return i;
+                }
+            }
+        }
+        return -1;
+    }
+
+    public int maximumBeauty(int[] nums, int k) {
+        Arrays.sort(nums);
+        int max = 0;
+        int index = 0;
+        for (int i = 1; i < nums.length; i++) {
+            while (nums[i] - nums[index] > k * 2) {
+                max = Math.max(max, i - index);
+                index++;
+            }
+        }
+        return Math.max(max, nums.length - index);
+    }
+
+    public int sumOfSquares(int[] nums) {
+        int sum = 0;
+        int size = nums.length;
+        for (int i = 0; i < size; i++) {
+            if (size % (i + 1) == 0) {
+                sum += nums[i] * nums[i];
+            }
+        }
+        return sum;
+    }
+}