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whai 2024-01-24 22:10:12 +08:00
parent 24c2458f4f
commit ca386eaae0
5 changed files with 327 additions and 0 deletions
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79
src/main/java/cn/whaifree/leetCode/Tree/LeetCode112.java Normal file
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package cn.whaifree.leetCode.Tree;
import cn.whaifree.leetCode.model.TreeNode;
import org.junit.Test;
import java.util.Deque;
/**
* @version 1.0
* @Author whai文海
* @Date 2024/1/24 20:59
* @注释
*/
public class LeetCode112 {
@Test
public void test(
) {
TreeNode treeNode = TreeNode.constructTree(new Integer[]{5,4,8,11,null,13,4,7,2,null,null,null,1});
treeNode.printTree();
System.out.println(new Solution1().hasPathSum(treeNode, 22));
}
class Solution {
public boolean hasPathSum(TreeNode root, int targetSum) {
return level(root, 0, targetSum);
}
public boolean level(TreeNode treeNode,int sum,int targetSum) {
if (treeNode == null) {
return false;
}
sum += treeNode.val;
// 最后一个必须是叶子节点
if (treeNode.left == null && treeNode.right == null && sum == targetSum) {
return true;
}
boolean left = level(treeNode.left, sum, targetSum);
boolean right = level(treeNode.right, sum, targetSum);
return left || right;
}
}
class Solution1 {
/**
* 使用队列
* @param root
* @param targetSum
* @return
*/
public boolean hasPathSum(TreeNode root, int targetSum) {
if (root == null) {
return false;
}
Deque<Object> queue = new java.util.ArrayDeque<>();
queue.add(root);
queue.add(root.val);
while (!queue.isEmpty()) {
TreeNode pop = (TreeNode) queue.pop();
Integer value = (Integer) queue.pop();
if (pop.right == null && pop.left == null && value == targetSum) {
return true;
}
if (pop.right != null) {
queue.add(pop.right);
queue.add(value + pop.right.val);
}
if (pop.left != null) {
queue.add(pop.left);
queue.add(value + pop.left.val);
}
}
return false;
}
}
}

62
src/main/java/cn/whaifree/leetCode/Tree/LeetCode113.java Normal file
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package cn.whaifree.leetCode.Tree;
import cn.whaifree.leetCode.model.TreeNode;
import org.junit.Test;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
/**
* @version 1.0
* @Author whai文海
* @Date 2024/1/24 21:30
* @注释
*/
public class LeetCode113 {
@Test
public void test() {
TreeNode treeNode = TreeNode.constructTree(new Integer[]{5,4,8,null,4});
treeNode.printTree();
System.out.println(new Solution().pathSum(treeNode, 13));
}
class Solution {
List<List<Integer>> res = new ArrayList<>();
public List<List<Integer>> pathSum(TreeNode root, int targetSum) {
if (root == null) {
return res;
}
level(root, targetSum, new ArrayList<>());
return res;
}
/**
*
* @param root 节点
* @param needSum 还需要的数
* @param nowHasPath 记录已经走过的路，也用于回退
*/
public void level(TreeNode root, int needSum,ArrayList<Integer> nowHasPath) {
if (root == null) {
return;
}
nowHasPath.add(root.val);
if (root.left == null && root.right == null && root.val == needSum) {
res.add(new ArrayList<>(nowHasPath));
// 回退全部交给上一次递归
}
if (root.left != null) {
level(root.left, needSum - root.val, nowHasPath);
nowHasPath.remove(nowHasPath.size() - 1);
}
if (root.right != null) {
level(root.right, needSum - root.val, nowHasPath);
nowHasPath.remove(nowHasPath.size() - 1);
}
}
}
}

96
src/main/java/cn/whaifree/leetCode/Tree/LeetCode404.java Normal file
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package cn.whaifree.leetCode.Tree;
import cn.whaifree.leetCode.model.TreeNode;
import com.sun.org.apache.regexp.internal.RE;
import org.junit.Test;
import java.util.Deque;
import java.util.LinkedList;
/**
* @version 1.0
* @Author whai文海
* @Date 2024/1/24 19:03
* @注释
*/
public class LeetCode404 {
@Test
public void test(){
TreeNode treeNode = TreeNode.constructTree(new Integer[]{3,9,20,null,null,15,7});
treeNode.printTree();
System.out.println(new Solution2().sumOfLeftLeaves(treeNode));
}
class Solution {
public int sumOfLeftLeaves(TreeNode root) {
if (root == null) {
return 0;
}
int right = sumOfLeftLeaves(root.right);
int left = sumOfLeftLeaves(root.left);
// 如果左边存在，且是叶子节点，再返回
if (root.left != null && root.left.left == null && root.left.right == null) {
return left + right + root.left.val;
}
return left + right;
}
}
class Solution1 {
public int sumOfLeftLeaves(TreeNode root) {
if (root == null) {
return 0;
}
Deque<TreeNode> stack = new LinkedList<>();
stack.push(root);
// 遍历
while (!stack.isEmpty()) {
TreeNode pop = stack.pop();
if (pop != null) {
// 遇到没进入过的节点
if (pop.right!=null) stack.push(pop.right);
if (pop.left!=null) stack.push(pop.left);
stack.push(pop);
stack.push(null);
} else {
TreeNode pop1 = stack.pop();
// if (pop1.left.left == null && pop1.left.right == null) {
//
// }
}
}
return 1;
}
}
class Solution2 {
public int sumOfLeftLeaves(TreeNode root) {
if (root == null) {
return 0;
}
Deque<TreeNode> deque= new LinkedList<>();
deque.add(root);
// 遍历
int sum = 0;
while (!deque.isEmpty()) {
TreeNode pop = deque.pop();
if (pop.right != null) {
deque.add(pop.right);
}
if (pop.left != null) {
// left是叶子节点，并且是左边
if (pop.left.right == null && pop.left.left == null) {
sum += pop.left.val;
}
deque.add(pop.left);
}
}
return sum;
}
}
}

77
src/main/java/cn/whaifree/leetCode/Tree/LeetCode513.java Normal file
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package cn.whaifree.leetCode.Tree;
import cn.whaifree.leetCode.model.TreeNode;
import javafx.scene.layout.VBox;
import org.junit.Test;
import java.util.ArrayList;
import java.util.Deque;
import java.util.List;
/**
* @version 1.0
* @Author whai文海
* @Date 2024/1/24 19:35
* @注释
*/
public class LeetCode513 {
@Test
public void test() {
TreeNode root = TreeNode.constructTree(new Integer[]{1});
root.printTree();
System.out.println(new Solution1().findBottomLeftValue(root));
}
class Solution {
public int findBottomLeftValue(TreeNode root) {
if (root == null) {
return 0;
}
ArrayList<List<Integer>> e = new ArrayList<>();
Deque<TreeNode> deque = new java.util.LinkedList<>();
deque.add(root);
int res = 0;
while (!deque.isEmpty()) {
int size = deque.size();
while (size-- > 0) {
TreeNode pop = deque.pop();
if (pop.right!=null) deque.add(pop.right);
if (pop.left!=null) deque.add(pop.left);
if (deque.isEmpty()) {
res = pop.val;
}
}
}
return res;
}
}
class Solution1 {
Integer depth = 0;
Integer res = 0;
public int findBottomLeftValue(TreeNode root) {
// 只有一个节点
if (root.left==null&&root.right==null) return root.val;
level(root, 0);
return res;
}
public void level(TreeNode root, int level) {
if (root == null) {
return;
}
if (root.right == null && root.left == null) {
if (level > depth) {
depth = level;
res = root.val;
}
// 遇到每层层第一个叶子节点，就可能是叶子节点，如果层数更深，那么就替换
return;
}
level(root.left, level + 1);
level(root.right, level + 1);
}
}
}

13
src/main/java/cn/whaifree/leetCode/model/TreeNode.java
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@ -1,6 +1,7 @@
package cn.whaifree.leetCode.model;
import java.util.*;
import java.util.function.Consumer;
/**
* @version 1.0
@ -132,6 +133,18 @@ public class TreeNode {
return true;
}
public static TreeNode constructRandom(Integer number) {
Random random = new Random();
List<Integer> tree = new ArrayList<Integer>();
for (int i = 0; i < number; i++) {
tree.add(random.nextInt(10));
}
// 将Arraylist变为数组
Integer[] objects = tree.toArray(new Integer[tree.size()]);
return constructTree(objects);
}
public static TreeNode constructTree(Integer[] array) {
if (array == null || array.length == 0 || array[0] == null) {
return null;