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Commit c7fe128

Browse files
Merge branch 'master' of github.com:youngyangyang04/leetcode-master
2 parents 9b40338 + 12582fd commit c7fe128

20 files changed

+665
-40
lines changed

‎README.md‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -397,9 +397,9 @@
397397
* [图论:417.太平洋大西洋水流问题](./problems/0417.太平洋大西洋水流问题.md)
398398
* [图论:827.最大人工岛](./problems/0827.最大人工岛.md)
399399
* [图论:127. 单词接龙](./problems/0127.单词接龙.md)
400-
* [图论:841.钥匙和房间](./problems/841.钥匙和房间)
400+
* [图论:841.钥匙和房间](./problems/0841.钥匙和房间.md)
401401
* [图论:463. 岛屿的周长](./problems/0463.岛屿的周长.md)
402-
* [图论:并查集理论基础](./problems/)
402+
* [图论:并查集理论基础](./problems/图论并查集理论基础.md)
403403
* [图论:1971. 寻找图中是否存在路径](./problems/1971.寻找图中是否存在路径.md)
404404
* [图论:684.冗余连接](./problems/0684.冗余连接.md)
405405
* [图论:685.冗余连接II](./problems/0685.冗余连接II.md)

‎problems/0070.爬楼梯完全背包版本.md‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -100,8 +100,8 @@ int main() {
100100
while (cin >> n >> m) {
101101
vector<int> dp(n + 1, 0);
102102
dp[0] = 1;
103-
for (int i = 1; i <= n; i++) { // 遍历物品
104-
for (int j = 1; j <= m; j++) { // 遍历背包
103+
for (int i = 1; i <= n; i++) { // 遍历背包
104+
for (int j = 1; j <= m; j++) { // 遍历物品
105105
if (i - j >= 0) dp[i] += dp[i - j];
106106
}
107107
}

‎problems/0101.对称二叉树.md‎

Lines changed: 47 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -897,6 +897,53 @@ impl Solution {
897897
}
898898
}
899899
```
900+
### C#
901+
```C#
902+
// 递归
903+
public bool IsSymmetric(TreeNode root)
904+
{
905+
if (root == null) return true;
906+
return Compare(root.left, root.right);
907+
}
908+
public bool Compare(TreeNode left, TreeNode right)
909+
{
910+
if(left == null && right != null) return false;
911+
else if(left != null && right == null ) return false;
912+
else if(left == null && right == null) return true;
913+
else if(left.val != right.val) return false;
914+
915+
var outside = Compare(left.left, right.right);
916+
var inside = Compare(left.right, right.left);
917+
918+
return outside&&inside;
919+
}
920+
```
921+
``` C#
922+
// 迭代法
923+
public bool IsSymmetric(TreeNode root)
924+
{
925+
if (root == null) return true;
926+
var st = new Stack<TreeNode>();
927+
st.Push(root.left);
928+
st.Push(root.right);
929+
while (st.Count != 0)
930+
{
931+
var left = st.Pop();
932+
var right = st.Pop();
933+
if (left == null && right == null)
934+
continue;
935+
936+
if ((left == null || right == null || (left.val != right.val)))
937+
return false;
938+
939+
st.Push(left.left);
940+
st.Push(right.right);
941+
st.Push(left.right);
942+
st.Push(right.left);
943+
}
944+
return true;
945+
}
946+
```
900947

901948
<p align="center">
902949
<a href="https://programmercarl.com/other/kstar.html" target="_blank">

‎problems/0102.二叉树的层序遍历.md‎

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Original file line numberDiff line numberDiff line change
@@ -462,6 +462,32 @@ impl Solution {
462462
}
463463
}
464464
```
465+
### C#
466+
```C#
467+
public IList<IList<int>> LevelOrder(TreeNode root)
468+
{
469+
var res = new List<IList<int>>();
470+
var que = new Queue<TreeNode>();
471+
if (root == null) return res;
472+
que.Enqueue(root);
473+
while (que.Count != 0)
474+
{
475+
var size = que.Count;
476+
var vec = new List<int>();
477+
for (int i = 0; i < size; i++)
478+
{
479+
var cur = que.Dequeue();
480+
vec.Add(cur.val);
481+
if (cur.left != null) que.Enqueue(cur.left);
482+
if (cur.right != null) que.Enqueue(cur.right);
483+
}
484+
res.Add(vec);
485+
486+
487+
}
488+
return res;
489+
}
490+
```
465491

466492

467493
**此时我们就掌握了二叉树的层序遍历了,那么如下九道力扣上的题目,只需要修改模板的两三行代码(不能再多了),便可打倒!**
@@ -798,6 +824,31 @@ impl Solution {
798824
}
799825
}
800826
```
827+
### C#
828+
```C#
829+
public IList<IList<int>> LevelOrderBottom(TreeNode root)
830+
{
831+
var res = new List<IList<int>>();
832+
var que = new Queue<TreeNode>();
833+
if (root == null) return res;
834+
que.Enqueue(root);
835+
while (que.Count != 0)
836+
{
837+
var size = que.Count;
838+
var vec = new List<int>();
839+
for (int i = 0; i < size; i++)
840+
{
841+
var cur = que.Dequeue();
842+
vec.Add(cur.val);
843+
if (cur.left != null) que.Enqueue(cur.left);
844+
if (cur.right != null) que.Enqueue(cur.right);
845+
}
846+
res.Add(vec);
847+
}
848+
res.Reverse();
849+
return res;
850+
}
851+
```
801852

802853
## 199.二叉树的右视图
803854

‎problems/0104.二叉树的最大深度.md‎

Lines changed: 81 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -738,26 +738,36 @@ function maxDepth(root: TreeNode | null): number {
738738

739739
```typescript
740740
// 后续遍历(自下而上)
741-
function maxDepth(root: TreeNode | null): number {
742-
if (root === null) return 0;
743-
return Math.max(maxDepth(root.left), maxDepth(root.right)) + 1;
744-
};
741+
function maxDepth(root: Node | null): number {
742+
if (root === null) return 0
743+
let depth = 0
744+
for (let i = 0; i < root.children.length; i++) {
745+
depth = Math.max(depth, maxDepth(root.children[i]))
746+
}
747+
return depth + 1
748+
}
745749

746750
// 前序遍历(自上而下)
747-
function maxDepth(root: TreeNode | null): number {
748-
function recur(node: TreeNode | null, count: number) {
749-
if (node === null) {
750-
resMax = resMax > count ? resMax : count;
751-
return;
751+
function maxDepth(root: Node | null): number {
752+
if (root === null) return 0
753+
754+
let depth: number = 0
755+
const queue: Array<Node | null> = []
756+
queue.push(root)
757+
758+
while (queue.length > 0) {
759+
let len = queue.length
760+
depth++
761+
for (let i = 0; i < len; i++) {
762+
// 当前层遍历
763+
let curNode: Node | null = queue.shift()!
764+
for (let j = 0; j < curNode.children.length; j++) {
765+
if (curNode.children[j]) queue.push(curNode.children[j])
766+
}
752767
}
753-
recur(node.left, count + 1);
754-
recur(node.right, count + 1);
755768
}
756-
let resMax: number = 0;
757-
let count: number = 0;
758-
recur(root, count);
759-
return resMax;
760-
};
769+
return depth
770+
}
761771

762772

763773
```
@@ -1022,6 +1032,61 @@ impl Solution {
10221032
max_depth
10231033
}
10241034
```
1035+
### C#
1036+
```C#
1037+
// 递归法
1038+
public int MaxDepth(TreeNode root) {
1039+
if(root == null) return 0;
1040+
1041+
int leftDepth = MaxDepth(root.left);
1042+
int rightDepth = MaxDepth(root.right);
1043+
1044+
return 1 + Math.Max(leftDepth, rightDepth);
1045+
}
1046+
```
1047+
```C#
1048+
// 前序遍历
1049+
int result = 0;
1050+
public int MaxDepth(TreeNode root)
1051+
{
1052+
if (root == null) return result;
1053+
GetDepth(root, 1);
1054+
return result;
1055+
}
1056+
public void GetDepth(TreeNode root, int depth)
1057+
{
1058+
result = depth > result ? depth : result;
1059+
if (root.left == null && root.right == null) return;
1060+
1061+
if (root.left != null)
1062+
GetDepth(root.left, depth + 1);
1063+
if (root.right != null)
1064+
GetDepth(root.right, depth + 1);
1065+
return;
1066+
}
1067+
```
1068+
```C#
1069+
// 迭代法
1070+
public int MaxDepth(TreeNode root)
1071+
{
1072+
int depth = 0;
1073+
Queue<TreeNode> que = new();
1074+
if (root == null) return depth;
1075+
que.Enqueue(root);
1076+
while (que.Count != 0)
1077+
{
1078+
int size = que.Count;
1079+
depth++;
1080+
for (int i = 0; i < size; i++)
1081+
{
1082+
var node = que.Dequeue();
1083+
if (node.left != null) que.Enqueue(node.left);
1084+
if (node.right != null) que.Enqueue(node.right);
1085+
}
1086+
}
1087+
return depth;
1088+
}
1089+
```
10251090

10261091
<p align="center">
10271092
<a href="https://programmercarl.com/other/kstar.html" target="_blank">

‎problems/0110.平衡二叉树.md‎

Lines changed: 25 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -908,6 +908,31 @@ impl Solution {
908908
}
909909
}
910910
```
911+
### C#
912+
```C#
913+
public bool IsBalanced(TreeNode root)
914+
{
915+
return GetHeight(root) == -1 ? false : true;
916+
}
917+
public int GetHeight(TreeNode root)
918+
{
919+
if (root == null) return 0;
920+
int left = GetHeight(root.left);
921+
if (left == -1) return -1;
922+
int right = GetHeight(root.right);
923+
if (right == -1) return -1;
924+
int res;
925+
if (Math.Abs(left - right) > 1)
926+
{
927+
res = -1;
928+
}
929+
else
930+
{
931+
res = 1 + Math.Max(left, right);
932+
}
933+
return res;
934+
}
935+
```
911936

912937
<p align="center">
913938
<a href="https://programmercarl.com/other/kstar.html" target="_blank">

‎problems/0111.二叉树的最小深度.md‎

Lines changed: 43 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -708,6 +708,49 @@ impl Solution {
708708
}
709709
}
710710
```
711+
### C#
712+
```C#
713+
// 递归
714+
public int MinDepth(TreeNode root)
715+
{
716+
if (root == null) return 0;
717+
int left = MinDepth(root.left);
718+
int right = MinDepth(root.right);
719+
if (root.left == null && root.right != null)
720+
return 1+right;
721+
else if(root.left!=null && root.right == null)
722+
return 1+left;
723+
724+
int res = 1 + Math.Min(left, right);
725+
return res;
726+
}
727+
```
728+
```C#
729+
// 迭代
730+
public int MinDepth(TreeNode root)
731+
{
732+
if (root == null) return 0;
733+
int depth = 0;
734+
var que = new Queue<TreeNode>();
735+
que.Enqueue(root);
736+
while (que.Count > 0)
737+
{
738+
int size = que.Count;
739+
depth++;
740+
for (int i = 0; i < size; i++)
741+
{
742+
var node = que.Dequeue();
743+
if (node.left != null)
744+
que.Enqueue(node.left);
745+
if (node.right != null)
746+
que.Enqueue(node.right);
747+
if (node.left == null && node.right == null)
748+
return depth;
749+
}
750+
}
751+
return depth;
752+
}
753+
```
711754

712755
<p align="center">
713756
<a href="https://programmercarl.com/other/kstar.html" target="_blank">

‎problems/0112.路径总和.md‎

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Original file line numberDiff line numberDiff line change
@@ -1511,6 +1511,17 @@ impl Solution {
15111511
}
15121512
}
15131513

1514+
```
1515+
### C#
1516+
```C#
1517+
// 0112.路径总和
1518+
// 递归
1519+
public bool HasPathSum(TreeNode root, int targetSum)
1520+
{
1521+
if (root == null) return false;
1522+
if (root.left == null && root.right == null && targetSum == root.val) return true;
1523+
return HasPathSum(root.left, targetSum - root.val) || HasPathSum(root.right, targetSum - root.val);
1524+
}
15141525
```
15151526

15161527
<p align="center">

‎problems/0222.完全二叉树的节点个数.md‎

Lines changed: 25 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -867,6 +867,31 @@ impl Solution {
867867
}
868868
}
869869
```
870+
### C#
871+
```C#
872+
// 递归
873+
public int CountNodes(TreeNode root)
874+
{
875+
if (root == null) return 0;
876+
var left = root.left;
877+
var right = root.right;
878+
int leftDepth = 0, rightDepth = 0;
879+
while (left != null)
880+
{
881+
left = left.left;
882+
leftDepth++;
883+
}
884+
while (right != null)
885+
{
886+
right = right.right;
887+
rightDepth++;
888+
}
889+
if (leftDepth == rightDepth)
890+
return (int)Math.Pow(2, leftDepth+1) - 1;
891+
return CountNodes(root.left) + CountNodes(root.right) + 1;
892+
893+
}
894+
```
870895

871896
<p align="center">
872897
<a href="https://programmercarl.com/other/kstar.html" target="_blank">

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