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feat: add solutions to lc problem: No.0739 #3802

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Nov 22, 2024
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feat: add solutions to lc problem: No.0739 #3802

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196 changes: 68 additions & 128 deletions solution/0700-0799/0739.Daily Temperatures/README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -59,21 +59,13 @@ tags:

### 方法一：单调栈

单调栈常见模型：找出每个数左/右边**离它最近的**且**比它大/小的数**。模板：
本题需要我们找出每个元素右边第一个比它大的元素的位置，这是一个典型的单调栈应用场景。

```python
stk = []
for i in range(n):
while stk and check(stk[-1], i):
stk.pop()
stk.append(i)
```
我们从右往左遍历数组 $\textit{temperatures}$，维护一个从栈顶到栈底温度单调递增的栈 $\textit{stk}$，栈中存储的是数组元素的下标。对于每个元素 $\textit{temperatures}[i]$，我们不断将其与栈顶元素进行比较，如果栈顶元素对应的温度小于等于 $\textit{temperatures}[i]$，那么循环将栈顶元素弹出，直到栈为空或者栈顶元素对应的温度大于 $\textit{temperatures}[i]$。此时，栈顶元素就是右边第一个比 $\textit{temperatures}[i]$ 大的元素，距离为 $\textit{stk.top()} - i$，我们更新答案数组。然后将 $\textit{temperatures}[i]$ 入栈，继续遍历。

对于本题，我们需要找出每个数右边**离它最近的**且**比它大的数**，因此我们可以从右往左遍历数组，且需要维护一个从栈底到栈顶单调递减的栈。
遍历结束后，返回答案数组即可。

对于当前遍历到的数 `temperatures[i]`，如果栈顶元素 `temperatures[stk[-1]]` 小于等于 `temperatures[i]`，则弹出栈顶元素，直到栈为空或者栈顶元素大于 `temperatures[i]`。如果此时栈不为空，那么栈顶元素就是 `temperatures[i]` 右边离它最近的且比它大的数，更新 `ans[i] = stk[-1] - i`。接着，我们将 $i$ 入栈，继续遍历下一个数。

时间复杂度 $O(n)$，空间复杂度 $O(n)$。其中 $n$ 为 `temperatures` 数组的长度。
时间复杂度 $O(n)$，空间复杂度 $O(n)$。其中 $n$ 为数组 $\textit{temperatures}$ 的长度。

<!-- tabs:start -->

Expand All @@ -82,12 +74,14 @@ for i in range(n):
```python
class Solution:
def dailyTemperatures(self, temperatures: List[int]) -> List[int]:
ans = [0] * len(temperatures)
stk = []
for i, t in enumerate(temperatures):
while stk and temperatures[stk[-1]] < t:
j = stk.pop()
ans[j] = i - j
n = len(temperatures)
ans = [0] * n
for i in range(n - 1, -1, -1):
while stk and temperatures[stk[-1]] <= temperatures[i]:
stk.pop()
if stk:
ans[i] = stk[-1] - i
stk.append(i)
return ans
```
Expand All @@ -98,12 +92,14 @@ class Solution:
class Solution {
public int[] dailyTemperatures(int[] temperatures) {
int n = temperatures.length;
int[] ans = new int[n];
Deque<Integer> stk = new ArrayDeque<>();
for (int i = 0; i < n; ++i) {
while (!stk.isEmpty() && temperatures[stk.peek()] < temperatures[i]) {
int j = stk.pop();
ans[j] = i - j;
int[] ans = new int[n];
for (int i = n - 1; i >= 0; --i) {
while (!stk.isEmpty() && temperatures[stk.peek()] <= temperatures[i]) {
stk.pop();
}
if (!stk.isEmpty()) {
ans[i] = stk.peek() - i;
}
stk.push(i);
}
Expand All @@ -119,13 +115,15 @@ class Solution {
public:
vector<int> dailyTemperatures(vector<int>& temperatures) {
int n = temperatures.size();
vector<int> ans(n);
stack<int> stk;
for (int i = 0; i < n; ++i) {
while (!stk.empty() && temperatures[stk.top()] < temperatures[i]) {
ans[stk.top()] = i - stk.top();
vector<int> ans(n);
for (int i = n - 1; ~i; --i) {
while (!stk.empty() && temperatures[stk.top()] <= temperatures[i]) {
stk.pop();
}
if (!stk.empty()) {
ans[i] = stk.top() - i;
}
stk.push(i);
}
return ans;
Expand All @@ -137,14 +135,16 @@ public:

```go
func dailyTemperatures(temperatures []int) []int {
ans := make([]int, len(temperatures))
var stk []int
for i, t := range temperatures {
for len(stk) > 0 && temperatures[stk[len(stk)-1]] < t {
j := stk[len(stk)-1]
ans[j] = i - j
n := len(temperatures)
ans := make([]int, n)
stk := []int{}
for i := n - 1; i >= 0; i-- {
for len(stk) > 0 && temperatures[stk[len(stk)-1]] <= temperatures[i] {
stk = stk[:len(stk)-1]
}
if len(stk) > 0 {
ans[i] = stk[len(stk)-1] - i
}
stk = append(stk, i)
}
return ans
Expand All @@ -156,14 +156,14 @@ func dailyTemperatures(temperatures []int) []int {
```ts
function dailyTemperatures(temperatures: number[]): number[] {
const n = temperatures.length;
const ans = new Array(n).fill(0);
const ans: number[] = Array(n).fill(0);
const stk: number[] = [];
for (let i = n - 1; i >= 0; --i) {
while (stk.length && temperatures[stk[stk.length - 1]] <= temperatures[i]) {
for (let i = n - 1; ~i; --i) {
while (stk.length && temperatures[stk.at(-1)!] <= temperatures[i]) {
stk.pop();
}
if (stk.length) {
ans[i] = stk[stk.length - 1] - i;
ans[i] = stk.at(-1)! - i;
}
stk.push(i);
}
Expand Down Expand Up @@ -191,6 +191,34 @@ impl Solution {
}
```

#### Rust

```rust
impl Solution {
pub fn daily_temperatures(temperatures: Vec<i32>) -> Vec<i32> {
let n = temperatures.len();
let mut stk: Vec<usize> = Vec::new();
let mut ans = vec![0; n];

for i in (0..n).rev() {
while let Some(&top) = stk.last() {
if temperatures[top] <= temperatures[i] {
stk.pop();
} else {
break;
}
}
if let Some(&top) = stk.last() {
ans[i] = (top - i) as i32;
}
stk.push(i);
}

ans
}
}
```

#### JavaScript

```js
Expand All @@ -200,14 +228,14 @@ impl Solution {
*/
var dailyTemperatures = function (temperatures) {
const n = temperatures.length;
const ans = new Array(n).fill(0);
const ans = Array(n).fill(0);
const stk = [];
for (let i = n - 1; i >= 0; --i) {
while (stk.length && temperatures[stk[stk.length - 1]] <= temperatures[i]) {
for (let i = n - 1; ~i; --i) {
while (stk.length && temperatures[stk.at(-1)] <= temperatures[i]) {
stk.pop();
}
if (stk.length) {
ans[i] = stk[stk.length - 1] - i;
ans[i] = stk.at(-1) - i;
}
stk.push(i);
}
Expand All @@ -219,92 +247,4 @@ var dailyTemperatures = function (temperatures) {

<!-- solution:end -->

<!-- solution:start -->

### 方法二

<!-- tabs:start -->

#### Python3

```python
class Solution:
def dailyTemperatures(self, temperatures: List[int]) -> List[int]:
n = len(temperatures)
stk = []
ans = [0] * n
for i in range(n - 1, -1, -1):
while stk and temperatures[stk[-1]] <= temperatures[i]:
stk.pop()
if stk:
ans[i] = stk[-1] - i
stk.append(i)
return ans
```

#### Java

```java
class Solution {
public int[] dailyTemperatures(int[] temperatures) {
int n = temperatures.length;
Deque<Integer> stk = new ArrayDeque<>();
int[] ans = new int[n];
for (int i = n - 1; i >= 0; --i) {
while (!stk.isEmpty() && temperatures[stk.peek()] <= temperatures[i]) {
stk.pop();
}
if (!stk.isEmpty()) {
ans[i] = stk.peek() - i;
}
stk.push(i);
}
return ans;
}
}
```

#### C++

```cpp
class Solution {
public:
vector<int> dailyTemperatures(vector<int>& temperatures) {
int n = temperatures.size();
vector<int> ans(n);
stack<int> stk;
for (int i = n - 1; ~i; --i) {
while (!stk.empty() && temperatures[stk.top()] <= temperatures[i]) stk.pop();
if (!stk.empty()) ans[i] = stk.top() - i;
stk.push(i);
}
return ans;
}
};
```

#### Go

```go
func dailyTemperatures(temperatures []int) []int {
n := len(temperatures)
ans := make([]int, n)
var stk []int
for i := n - 1; i >= 0; i-- {
for len(stk) > 0 && temperatures[stk[len(stk)-1]] <= temperatures[i] {
stk = stk[:len(stk)-1]
}
if len(stk) > 0 {
ans[i] = stk[len(stk)-1] - i
}
stk = append(stk, i)
}
return ans
}
```

<!-- tabs:end -->

<!-- solution:end -->

<!-- problem:end -->
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