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diff --git a/‎src/main/java/com/blankj/google/CountIslandWithTree.kt
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+33Lines changed: 33 additions & 0 deletions b/‎src/main/java/com/blankj/google/CountIslandWithTree.kt
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+33Lines changed: 33 additions & 0 deletions
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+package com.blankj.google
+
+import com.blankj.ext.print
+import com.blankj.structure.TreeNode
+import kotlin.math.max
+
+class CountIslandWithTree {
+    fun countIslands(root: TreeNode?): Int {
+        var count = 0
+        fun dfs(node: TreeNode?): Int {
+            if (node == null) return 0
+            val left = dfs(node.left)
+            val right = dfs(node.right)
+            // 如果当前节点为 1 且左右子节点都为 0，则表示找到一个新的岛屿
+            if (node.`val` == 1 && left == 0 && right == 0) {
+                count++
+            }
+            if (node.`val` == 1 && left == 1 && right == 1) {
+                count--
+            }
+            // 返回当前节点及其左右子节点组成的岛屿数量
+            return  node.`val`
+        }
+        dfs(root)
+        return count
+    }
+}
+
+fun main() {
+    CountIslandWithTree().countIslands(TreeNode.createTestData("[1,0,0,1,1,1]")).print()
+    CountIslandWithTree().countIslands(TreeNode.createTestData("[1,0,1,1,1,1]")).print()
+    CountIslandWithTree().countIslands(TreeNode.createTestData("[1,1,1,1,1,1]")).print()
+}