mirror of
https://github.com/youngyangyang04/leetcode-master.git
synced 2025-07-08 00:43:04 +08:00
Merge branch 'master' of github.com:youngyangyang04/leetcode-master
This commit is contained in:
programmercarl
@ -195,7 +195,7 @@ class Solution:
|
||||
break
|
||||
self.reverse(nums, i, length-1)
|
||||
break
|
||||
else:
|
||||
if n == 1:
|
||||
# 若正常结束循环，则对原数组直接翻转
|
||||
self.reverse(nums, 0, length-1)
|
||||
|
||||
|
||||
@ -488,6 +488,52 @@ function solveSudoku(board: string[][]): void {
|
||||
};
|
||||
```
|
||||
|
||||
### Rust
|
||||
|
||||
```Rust
|
||||
impl Solution {
|
||||
fn is_valid(row: usize, col: usize, val: char, board: &mut Vec<Vec<char>>) -> bool{
|
||||
for i in 0..9 {
|
||||
if board[row][i] == val { return false; }
|
||||
}
|
||||
for j in 0..9 {
|
||||
if board[j][col] == val {
|
||||
return false;
|
||||
}
|
||||
}
|
||||
let start_row = (row / 3) * 3;
|
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let start_col = (col / 3) * 3;
|
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for i in start_row..(start_row + 3) {
|
||||
for j in start_col..(start_col + 3) {
|
||||
if board[i][j] == val { return false; }
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||||
}
|
||||
}
|
||||
return true;
|
||||
}
|
||||
|
||||
fn backtracking(board: &mut Vec<Vec<char>>) -> bool{
|
||||
for i in 0..board.len() {
|
||||
for j in 0..board[0].len() {
|
||||
if board[i][j] != '.' { continue; }
|
||||
for k in '1'..='9' {
|
||||
if Self::is_valid(i, j, k, board) {
|
||||
board[i][j] = k;
|
||||
if Self::backtracking(board) { return true; }
|
||||
board[i][j] = '.';
|
||||
}
|
||||
}
|
||||
return false;
|
||||
}
|
||||
}
|
||||
return true;
|
||||
}
|
||||
|
||||
pub fn solve_sudoku(board: &mut Vec<Vec<char>>) {
|
||||
Self::backtracking(board);
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
### C
|
||||
|
||||
```C
|
||||
|
||||
@ -305,6 +305,56 @@ object Solution {
|
||||
}
|
||||
```
|
||||
|
||||
### Rust
|
||||
|
||||
```Rust
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||||
//版本一
|
||||
impl Solution {
|
||||
fn max(a: i32, b:i32) -> i32 {
|
||||
if a > b { a } else { b }
|
||||
}
|
||||
pub fn jump(nums: Vec<i32>) -> i32 {
|
||||
if nums.len() == 0 { return 0; }
|
||||
let mut cur_distance: i32 = 0;
|
||||
let mut ans: i32 = 0;
|
||||
let mut next_distance: i32 = 0;
|
||||
for i in 0..nums.len() {
|
||||
next_distance = Self::max(nums[i] + i as i32, next_distance);
|
||||
if i as i32 == cur_distance {
|
||||
if cur_distance != (nums.len() - 1) as i32 {
|
||||
ans += 1;
|
||||
cur_distance = next_distance;
|
||||
if next_distance == (nums.len() - 1) as i32 { break; }
|
||||
}
|
||||
else { break; }
|
||||
}
|
||||
}
|
||||
ans
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
```Rust
|
||||
//版本二
|
||||
impl Solution {
|
||||
fn max(a: i32, b:i32) -> i32 {
|
||||
if a > b { a } else { b }
|
||||
}
|
||||
pub fn jump(nums: Vec<i32>) -> i32 {
|
||||
let mut cur_distance: i32 = 0;
|
||||
let mut ans: i32 = 0;
|
||||
let mut next_distance: i32 = 0;
|
||||
for i in 0..nums.len() - 1 {
|
||||
next_distance = Self::max(nums[i] + i as i32, next_distance);
|
||||
if i as i32 == cur_distance {
|
||||
cur_distance = next_distance;
|
||||
ans += 1;
|
||||
}
|
||||
}
|
||||
ans
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
|
||||
-----------------------
|
||||
|
||||
@ -351,6 +351,40 @@ func permuteUnique(_ nums: [Int]) -> [[Int]] {
|
||||
}
|
||||
```
|
||||
|
||||
### Rust
|
||||
|
||||
```Rust
|
||||
impl Solution {
|
||||
fn backtracking(result: &mut Vec<Vec<i32>>, path: &mut Vec<i32>, nums: &Vec<i32>, used: &mut Vec<bool>) {
|
||||
let len = nums.len();
|
||||
if path.len() == len {
|
||||
result.push(path.clone());
|
||||
return;
|
||||
}
|
||||
for i in 0..len {
|
||||
if i > 0 && nums[i] == nums[i - 1] && used[i - 1] == false { continue; }
|
||||
if used[i] == false {
|
||||
used[i] = true;
|
||||
path.push(nums[i]);
|
||||
Self::backtracking(result, path, nums, used);
|
||||
path.pop();
|
||||
used[i] = false;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
pub fn permute_unique(nums: Vec<i32>) -> Vec<Vec<i32>> {
|
||||
let mut result: Vec<Vec<i32>> = Vec::new();
|
||||
let mut path: Vec<i32> = Vec::new();
|
||||
let mut used = vec![false; nums.len()];
|
||||
let mut nums= nums;
|
||||
nums.sort();
|
||||
Self::backtracking(&mut result, &mut path, &nums, &mut used);
|
||||
result
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
### C
|
||||
```c
|
||||
//临时数组
|
||||
|
||||
@ -558,6 +558,56 @@ func solveNQueens(_ n: Int) -> [[String]] {
|
||||
}
|
||||
```
|
||||
|
||||
### Rust
|
||||
|
||||
```Rust
|
||||
impl Solution {
|
||||
fn is_valid(row: usize, col: usize, chessboard: &mut Vec<Vec<char>>, n: usize) -> bool {
|
||||
let mut i = 0 as usize;
|
||||
while i < row {
|
||||
if chessboard[i][col] == 'Q' { return false; }
|
||||
i += 1;
|
||||
}
|
||||
let (mut i, mut j) = (row as i32 - 1, col as i32 - 1);
|
||||
while i >= 0 && j >= 0 {
|
||||
if chessboard[i as usize][j as usize] == 'Q' { return false; }
|
||||
i -= 1;
|
||||
j -= 1;
|
||||
}
|
||||
let (mut i, mut j) = (row as i32 - 1, col as i32 + 1);
|
||||
while i >= 0 && j < n as i32 {
|
||||
if chessboard[i as usize][j as usize] == 'Q' { return false; }
|
||||
i -= 1;
|
||||
j += 1;
|
||||
}
|
||||
return true;
|
||||
}
|
||||
fn backtracking(result: &mut Vec<Vec<String>>, n: usize, row: usize, chessboard: &mut Vec<Vec<char>>) {
|
||||
if row == n {
|
||||
let mut chessboard_clone: Vec<String> = Vec::new();
|
||||
for i in chessboard {
|
||||
chessboard_clone.push(i.iter().collect::<String>());
|
||||
}
|
||||
result.push(chessboard_clone);
|
||||
return;
|
||||
}
|
||||
for col in 0..n {
|
||||
if Self::is_valid(row, col, chessboard, n) {
|
||||
chessboard[row][col] = 'Q';
|
||||
Self::backtracking(result, n, row + 1, chessboard);
|
||||
chessboard[row][col] = '.';
|
||||
}
|
||||
}
|
||||
}
|
||||
pub fn solve_n_queens(n: i32) -> Vec<Vec<String>> {
|
||||
let mut result: Vec<Vec<String>> = Vec::new();
|
||||
let mut chessboard: Vec<Vec<char>> = vec![vec!['.'; n as usize]; n as usize];
|
||||
Self::backtracking(&mut result, n as usize, 0, &mut chessboard);
|
||||
result
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
### C
|
||||
```c
|
||||
char ***ans;
|
||||
|
||||
@ -154,6 +154,26 @@ var canJump = function(nums) {
|
||||
};
|
||||
```
|
||||
|
||||
### Rust
|
||||
|
||||
```Rust
|
||||
impl Solution {
|
||||
fn max(a: usize, b: usize) -> usize {
|
||||
if a > b { a } else { b }
|
||||
}
|
||||
pub fn can_jump(nums: Vec<i32>) -> bool {
|
||||
let mut cover = 0;
|
||||
if (nums.len() == 1) { return true; }
|
||||
let mut i = 0;
|
||||
while i <= cover {
|
||||
cover = Self::max(i + nums[i] as usize, cover);
|
||||
if cover >= nums.len() - 1 { return true; }
|
||||
i += 1;
|
||||
}
|
||||
false
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
### C
|
||||
```c
|
||||
|
||||
@ -292,6 +292,30 @@ function subsets(nums: number[]): number[][] {
|
||||
};
|
||||
```
|
||||
|
||||
## Rust
|
||||
|
||||
```Rust
|
||||
impl Solution {
|
||||
fn backtracking(result: &mut Vec<Vec<i32>>, path: &mut Vec<i32>, nums: &Vec<i32>, start_index: usize) {
|
||||
result.push(path.clone());
|
||||
let len = nums.len();
|
||||
// if start_index >= len { return; }
|
||||
for i in start_index..len {
|
||||
path.push(nums[i]);
|
||||
Self::backtracking(result, path, nums, i + 1);
|
||||
path.pop();
|
||||
}
|
||||
}
|
||||
|
||||
pub fn subsets(nums: Vec<i32>) -> Vec<Vec<i32>> {
|
||||
let mut result: Vec<Vec<i32>> = Vec::new();
|
||||
let mut path: Vec<i32> = Vec::new();
|
||||
Self::backtracking(&mut result, &mut path, &nums, 0);
|
||||
result
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
## C
|
||||
|
||||
```c
|
||||
|
||||
@ -367,6 +367,36 @@ function subsetsWithDup(nums: number[]): number[][] {
|
||||
};
|
||||
```
|
||||
|
||||
### Rust
|
||||
|
||||
```Rust
|
||||
impl Solution {
|
||||
fn backtracking(result: &mut Vec<Vec<i32>>, path: &mut Vec<i32>, nums: &Vec<i32>, start_index: usize, used: &mut Vec<bool>) {
|
||||
result.push(path.clone());
|
||||
let len = nums.len();
|
||||
// if start_index >= len { return; }
|
||||
for i in start_index..len {
|
||||
if i > 0 && nums[i] == nums[i - 1] && used[i - 1] == false { continue; }
|
||||
path.push(nums[i]);
|
||||
used[i] = true;
|
||||
Self::backtracking(result, path, nums, i + 1, used);
|
||||
used[i] = false;
|
||||
path.pop();
|
||||
}
|
||||
}
|
||||
|
||||
pub fn subsets_with_dup(nums: Vec<i32>) -> Vec<Vec<i32>> {
|
||||
let mut result: Vec<Vec<i32>> = Vec::new();
|
||||
let mut path: Vec<i32> = Vec::new();
|
||||
let mut used = vec![false; nums.len()];
|
||||
let mut nums = nums;
|
||||
nums.sort();
|
||||
Self::backtracking(&mut result, &mut path, &nums, 0, &mut used);
|
||||
result
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
### C
|
||||
|
||||
```c
|
||||
|
||||
@ -536,6 +536,53 @@ func isNormalIp(s string,startIndex,end int)bool{
|
||||
|
||||
```
|
||||
|
||||
## Rust
|
||||
|
||||
```Rust
|
||||
impl Solution {
|
||||
fn is_valid(s: &Vec<char>, start: usize, end: usize) -> bool {
|
||||
if start > end { return false; }
|
||||
if s[start] == '0' && start != end { return false; }
|
||||
let mut num = 0;
|
||||
for i in start..=end {
|
||||
if s[i] > '9' || s[i] < '0' { return false; }
|
||||
if let Some(digit) = s[i].to_digit(10) { num = num * 10 + digit; }
|
||||
if num > 255 { return false; }
|
||||
}
|
||||
true
|
||||
}
|
||||
|
||||
fn backtracking(result: &mut Vec<String>, s: &mut Vec<char>, start_index: usize, mut point_num: usize) {
|
||||
let len = s.len();
|
||||
if point_num == 3 {
|
||||
if Self::is_valid(s, start_index, len - 1) {
|
||||
result.push(s.iter().collect::<String>());
|
||||
}
|
||||
return;
|
||||
}
|
||||
for i in start_index..len {
|
||||
if Self::is_valid(s, start_index, i) {
|
||||
point_num += 1;
|
||||
s.insert(i + 1, '.');
|
||||
Self::backtracking(result, s, i + 2, point_num);
|
||||
point_num -= 1;
|
||||
s.remove(i + 1);
|
||||
} else { break; }
|
||||
}
|
||||
}
|
||||
|
||||
pub fn restore_ip_addresses(s: String) -> Vec<String> {
|
||||
let mut result: Vec<String> = Vec::new();
|
||||
let len = s.len();
|
||||
if len < 4 || len > 12 { return result; }
|
||||
let mut s = s.chars().collect::<Vec<char>>();
|
||||
Self::backtracking(&mut result, &mut s, 0, 0);
|
||||
result
|
||||
}
|
||||
|
||||
}
|
||||
```
|
||||
|
||||
## C
|
||||
```c
|
||||
//记录结果
|
||||
|
||||
@ -205,6 +205,36 @@ class Solution {
|
||||
|
||||
go:
|
||||
|
||||
```go
|
||||
/**
|
||||
102. 二叉树的递归遍历
|
||||
*/
|
||||
func levelOrder(root *TreeNode) [][]int {
|
||||
arr := [][]int{}
|
||||
|
||||
depth := 0
|
||||
|
||||
var order func(root *TreeNode, depth int)
|
||||
|
||||
order = func(root *TreeNode, depth int) {
|
||||
if root == nil {
|
||||
return
|
||||
}
|
||||
if len(arr) == depth {
|
||||
arr = append(arr, []int{})
|
||||
}
|
||||
arr[depth] = append(arr[depth], root.Val)
|
||||
|
||||
order(root.Left, depth+1)
|
||||
order(root.Right, depth+1)
|
||||
}
|
||||
|
||||
order(root, depth)
|
||||
|
||||
return arr
|
||||
}
|
||||
```
|
||||
|
||||
```go
|
||||
/**
|
||||
102. 二叉树的层序遍历
|
||||
|
||||
@ -282,6 +282,43 @@ function maxProfit(prices: number[]): number {
|
||||
};
|
||||
```
|
||||
|
||||
### Rust
|
||||
|
||||
贪心：
|
||||
```Rust
|
||||
impl Solution {
|
||||
fn max(a: i32, b: i32) -> i32 {
|
||||
if a > b { a } else { b }
|
||||
}
|
||||
pub fn max_profit(prices: Vec<i32>) -> i32 {
|
||||
let mut result = 0;
|
||||
for i in 1..prices.len() {
|
||||
result += Self::max(prices[i] - prices[i - 1], 0);
|
||||
}
|
||||
result
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
动态规划：
|
||||
```Rust
|
||||
impl Solution {
|
||||
fn max(a: i32, b: i32) -> i32 {
|
||||
if a > b { a } else { b }
|
||||
}
|
||||
pub fn max_profit(prices: Vec<i32>) -> i32 {
|
||||
let n = prices.len();
|
||||
let mut dp = vec![vec![0; 2]; n];
|
||||
dp[0][0] -= prices[0];
|
||||
for i in 1..n {
|
||||
dp[i][0] = Self::max(dp[i - 1][0], dp[i - 1][1] - prices[i]);
|
||||
dp[i][1] = Self::max(dp[i - 1][1], dp[i - 1][0] + prices[i]);
|
||||
}
|
||||
Self::max(dp[n - 1][0], dp[n - 1][1])
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
### C:
|
||||
贪心：
|
||||
```c
|
||||
|
||||
@ -742,5 +742,33 @@ func (p ticketSlice) Swap(i, j int) { p[i], p[j] = p[j], p[i] }
|
||||
|
||||
```
|
||||
|
||||
### Rust
|
||||
** 文中的Hashmap嵌套Hashmap的方法因为Rust的所有权问题暂时无法实现，此方法为删除哈希表中元素法 **
|
||||
```Rust
|
||||
use std::collections::HashMap;
|
||||
impl Solution {
|
||||
fn backtracking(airport: String, targets: &mut HashMap<&String, Vec<&String>>, result: &mut Vec<String>) {
|
||||
while let Some(next_airport) = targets.get_mut(&airport).unwrap_or(&mut vec![]).pop() {
|
||||
Self::backtracking(next_airport.clone(), targets, result);
|
||||
}
|
||||
result.push(airport.clone());
|
||||
}
|
||||
|
||||
pub fn find_itinerary(tickets: Vec<Vec<String>>) -> Vec<String> {
|
||||
let mut targets: HashMap<&String, Vec<&String>> = HashMap::new();
|
||||
let mut result = Vec::new();
|
||||
for t in 0..tickets.len() {
|
||||
targets.entry(&tickets[t][0]).or_default().push(&tickets[t][1]);
|
||||
}
|
||||
for (_, target) in targets.iter_mut() {
|
||||
target.sort_by(|a, b| b.cmp(a));
|
||||
}
|
||||
Self::backtracking("JFK".to_string(), &mut targets, &mut result);
|
||||
result.reverse();
|
||||
result
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
-----------------------
|
||||
<div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>
|
||||
|
||||
@ -353,18 +353,30 @@ class Solution:
|
||||
# self.left = left
|
||||
# self.right = right
|
||||
class Solution:
|
||||
def rob(self, root: TreeNode) -> int:
|
||||
result = self.rob_tree(root)
|
||||
return max(result[0], result[1])
|
||||
def rob(self, root: Optional[TreeNode]) -> int:
|
||||
# dp数组（dp table）以及下标的含义：
|
||||
# 1. 下标为 0 记录 **不偷该节点** 所得到的的最大金钱
|
||||
# 2. 下标为 1 记录 **偷该节点** 所得到的的最大金钱
|
||||
dp = self.traversal(root)
|
||||
return max(dp)
|
||||
|
||||
def rob_tree(self, node):
|
||||
if node is None:
|
||||
return (0, 0) # (偷当前节点金额，不偷当前节点金额)
|
||||
left = self.rob_tree(node.left)
|
||||
right = self.rob_tree(node.right)
|
||||
val1 = node.val + left[1] + right[1] # 偷当前节点，不能偷子节点
|
||||
val2 = max(left[0], left[1]) + max(right[0], right[1]) # 不偷当前节点，可偷可不偷子节点
|
||||
return (val1, val2)
|
||||
# 要用后序遍历, 因为要通过递归函数的返回值来做下一步计算
|
||||
def traversal(self, node):
|
||||
|
||||
# 递归终止条件，就是遇到了空节点，那肯定是不偷的
|
||||
if not node:
|
||||
return (0, 0)
|
||||
|
||||
left = self.traversal(node.left)
|
||||
right = self.traversal(node.right)
|
||||
|
||||
# 不偷当前节点, 偷子节点
|
||||
val_0 = max(left[0], left[1]) + max(right[0], right[1])
|
||||
|
||||
# 偷当前节点, 不偷子节点
|
||||
val_1 = node.val + left[0] + right[0]
|
||||
|
||||
return (val_0, val_1)
|
||||
```
|
||||
|
||||
### Go
|
||||
|
||||
@ -150,6 +150,7 @@ class Solution {
|
||||
int count = 1;
|
||||
//重叠气球的最小右边界
|
||||
int leftmostRightBound = points[0][1];
|
||||
for (int i = 1; i < points.length; i++) {
|
||||
//如果下一个气球的左边界大于最小右边界
|
||||
for(int i = 1; i < points.length; i++){
|
||||
if (points[i][0] > leftmostRightBound ) {
|
||||
|
||||
@ -423,6 +423,57 @@ function findSubsequences(nums: number[]): number[][] {
|
||||
};
|
||||
```
|
||||
|
||||
### Rust
|
||||
**回溯+哈希**
|
||||
```Rust
|
||||
use std::collections::HashSet;
|
||||
impl Solution {
|
||||
fn backtracking(result: &mut Vec<Vec<i32>>, path: &mut Vec<i32>, nums: &Vec<i32>, start_index: usize) {
|
||||
if path.len() > 1 { result.push(path.clone()); }
|
||||
let len = nums.len();
|
||||
let mut uset: HashSet<i32> = HashSet::new();
|
||||
for i in start_index..len {
|
||||
if (!path.is_empty() && nums[i] < *path.last().unwrap()) || uset.contains(&nums[i]) { continue; }
|
||||
uset.insert(nums[i]);
|
||||
path.push(nums[i]);
|
||||
Self::backtracking(result, path, nums, i + 1);
|
||||
path.pop();
|
||||
}
|
||||
}
|
||||
|
||||
pub fn find_subsequences(nums: Vec<i32>) -> Vec<Vec<i32>> {
|
||||
let mut result: Vec<Vec<i32>> = Vec::new();
|
||||
let mut path: Vec<i32> = Vec::new();
|
||||
Self::backtracking(&mut result, &mut path, &nums, 0);
|
||||
result
|
||||
}
|
||||
}
|
||||
```
|
||||
**回溯+数组**
|
||||
```Rust
|
||||
impl Solution {
|
||||
fn backtracking(result: &mut Vec<Vec<i32>>, path: &mut Vec<i32>, nums: &Vec<i32>, start_index: usize) {
|
||||
if path.len() > 1 { result.push(path.clone()); }
|
||||
let len = nums.len();
|
||||
let mut used = [0; 201];
|
||||
for i in start_index..len {
|
||||
if (!path.is_empty() && nums[i] < *path.last().unwrap()) || used[(nums[i] + 100) as usize] == 1 { continue; }
|
||||
used[(nums[i] + 100) as usize] = 1;
|
||||
path.push(nums[i]);
|
||||
Self::backtracking(result, path, nums, i + 1);
|
||||
path.pop();
|
||||
}
|
||||
}
|
||||
|
||||
pub fn find_subsequences(nums: Vec<i32>) -> Vec<Vec<i32>> {
|
||||
let mut result: Vec<Vec<i32>> = Vec::new();
|
||||
let mut path: Vec<i32> = Vec::new();
|
||||
Self::backtracking(&mut result, &mut path, &nums, 0);
|
||||
result
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
### C
|
||||
|
||||
```c
|
||||
|
||||
@ -227,6 +227,31 @@ var largestSumAfterKNegations = function(nums, k) {
|
||||
};
|
||||
```
|
||||
|
||||
### Rust
|
||||
|
||||
```Rust
|
||||
impl Solution {
|
||||
pub fn largest_sum_after_k_negations(nums: Vec<i32>, k: i32) -> i32 {
|
||||
let mut nums = nums;
|
||||
let mut k = k;
|
||||
let len = nums.len();
|
||||
nums.sort_by(|a, b| b.abs().cmp(&a.abs()));
|
||||
for i in 0..len {
|
||||
if nums[i] < 0 && k > 0 {
|
||||
nums[i] *= -1;
|
||||
k -= 1;
|
||||
}
|
||||
}
|
||||
if k % 2 == 1 { nums[len - 1] *= -1; }
|
||||
let mut result = 0;
|
||||
for num in nums {
|
||||
result += num;
|
||||
}
|
||||
result
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
|
||||
### C
|
||||
```c
|
||||
|
||||
@ -57,11 +57,18 @@ TreeNode* construct_binary_tree(const vector<int>& vec) {
|
||||
if (i == 0) root = node;
|
||||
}
|
||||
// 遍历一遍，根据规则左右孩子赋值就可以了
|
||||
// 注意这里 结束规则是 i * 2 + 2 < vec.size()，避免空指针
|
||||
for (int i = 0; i * 2 + 2 < vec.size(); i++) {
|
||||
// 注意这里 结束规则是 i * 2 + 1 < vec.size()，避免空指针
|
||||
// 为什么结束规则不能是i * 2 + 2 < arr.length呢?
|
||||
// 如果i * 2 + 2 < arr.length 是结束条件
|
||||
// 那么i * 2 + 1这个符合条件的节点就被忽略掉了
|
||||
// 例如[2,7,9,-1,1,9,6,-1,-1,10] 这样的一个二叉树,最后的10就会被忽略掉
|
||||
// 遍历一遍，根据规则左右孩子赋值就可以了
|
||||
|
||||
for (int i = 0; i * 2 + 1 < vec.size(); i++) {
|
||||
if (vecTree[i] != NULL) {
|
||||
// 线性存储转连式存储关键逻辑
|
||||
vecTree[i]->left = vecTree[i * 2 + 1];
|
||||
if(i * 2 + 2 < vec.size())
|
||||
vecTree[i]->right = vecTree[i * 2 + 2];
|
||||
}
|
||||
}
|
||||
@ -114,9 +121,10 @@ TreeNode* construct_binary_tree(const vector<int>& vec) {
|
||||
vecTree[i] = node;
|
||||
if (i == 0) root = node;
|
||||
}
|
||||
for (int i = 0; i * 2 + 2 < vec.size(); i++) {
|
||||
for (int i = 0; i * 2 + 1 < vec.size(); i++) {
|
||||
if (vecTree[i] != NULL) {
|
||||
vecTree[i]->left = vecTree[i * 2 + 1];
|
||||
if(i * 2 + 2 < vec.size())
|
||||
vecTree[i]->right = vecTree[i * 2 + 2];
|
||||
}
|
||||
}
|
||||
@ -249,12 +257,18 @@ public class Solution {
|
||||
}
|
||||
}
|
||||
// 遍历一遍，根据规则左右孩子赋值就可以了
|
||||
// 注意这里 结束规则是 i * 2 + 2 < arr.length，避免空指针
|
||||
for (int i = 0; i * 2 + 2 < arr.length; i++) {
|
||||
// 注意这里 结束规则是 i * 2 + 1 < arr.length，避免空指针
|
||||
// 为什么结束规则不能是i * 2 + 2 < arr.length呢?
|
||||
// 如果i * 2 + 2 < arr.length 是结束条件
|
||||
// 那么i * 2 + 1这个符合条件的节点就被忽略掉了
|
||||
// 例如[2,7,9,-1,1,9,6,-1,-1,10] 这样的一个二叉树,最后的10就会被忽略掉
|
||||
for (int i = 0; i * 2 + 1 < arr.length; i++) {
|
||||
TreeNode node = treeNodeList.get(i);
|
||||
if (node != null) {
|
||||
// 线性存储转连式存储关键逻辑
|
||||
node.left = treeNodeList.get(2 * i + 1);
|
||||
// 再次判断下 不忽略任何一个节点
|
||||
if(i * 2 + 2 < arr.length)
|
||||
node.right = treeNodeList.get(2 * i + 2);
|
||||
}
|
||||
}
|
||||
|
||||
@ -263,6 +263,13 @@ function reverseLeftWords(s: string, n: number): string {
|
||||
return strArr.join('');
|
||||
};
|
||||
```
|
||||
方法二:
|
||||
```typescript
|
||||
// 拼接两个字符串，截取符合要求的部分
|
||||
function reverseLeftWords(s: string, n: number): string {
|
||||
return (s+s).slice(n,s.length+n);
|
||||
};
|
||||
```
|
||||
|
||||
Swift:
|
||||
|
||||
|
||||
Reference in New Issue
Block a user