diff --git a/src/main/java/com/dota/arr/_3397/Solution.java b/src/main/java/com/dota/arr/_3397/Solution.java
new file mode 100644
index 0000000..5485e6b
--- /dev/null
+++ b/src/main/java/com/dota/arr/_3397/Solution.java
@@ -0,0 +1,23 @@
+package com.dota.arr._3397;
+
+import java.util.Arrays;
+
+class Solution {
+	public int maxDistinctElements(int[] nums, int k) {
+		Arrays.sort(nums);
+		var res = 1;
+		int n = nums.length;
+		nums[0] -= k;
+		int pre = nums[0];
+		for (int i = 1; i < n; i++) {
+			int t = nums[i];
+			t = Math.min(Math.max(pre + 1, t-k), t + k);
+			if(t>nums[i]) {
+				res++;
+				pre = t;
+			}
+		}
+
+		return res;
+	}
+}
\ No newline at end of file
diff --git a/src/main/java/com/dota/graph/_924/Solution.java b/src/main/java/com/dota/graph/_924/Solution.java
new file mode 100644
index 0000000..c9a7da0
--- /dev/null
+++ b/src/main/java/com/dota/graph/_924/Solution.java
@@ -0,0 +1,59 @@
+package com.dota.graph._924;
+
+import java.util.*;
+
+class Solution {
+	public int minMalwareSpread(int[][] graph, int[] initial) {
+		int n = graph.length;
+		//建立图
+		List<List<Integer>> g = new ArrayList<>();
+		for (int i = 0; i < n; i++) {
+			g.add(new ArrayList<>());
+		}
+
+		for (int i = 0; i < graph.length; i++) {
+			for (int j = i+1; j < graph[i].length; j++) {
+				if (graph[i][j] == 1) {
+					g.get(i).add(j);
+					g.get(j).add(i);
+				}
+			}
+		}
+
+		//最小索引
+		int res = initial[0];
+		//最小感染数
+		int min = Integer.MAX_VALUE;
+		Arrays.sort(initial);
+		for (int i : initial) {
+			var size = cal(n, g, initial, i);
+			if (size < min) {
+				res = i;
+				min = size;
+			}
+		}
+
+		return res;
+	}
+
+	int cal(int n, List<List<Integer>> list, int[] initial, int skip) {
+		var set = new HashSet<Integer>();
+		var visited = new boolean[n];
+		for (int i = 0; i < initial.length; i++) {
+			if (initial[i] == skip || visited[initial[i]]) continue;
+			df(list, initial[i], set, visited);
+		}
+
+		return set.size();
+	}
+
+	void df(List<List<Integer>> list, int i, Set<Integer> set, boolean[] visited) {
+		set.add(i);
+		visited[i] = true;
+		for (Integer j : list.get(i)) {
+			if (!visited[j]) {
+				df(list, j, set, visited);
+			}
+		}
+	}
+}
\ No newline at end of file