Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

feat: add solutions to lc problem: No.0907 #2021

Merged
merged 1 commit into from
Nov 27, 2023
+401 −257
Merged

feat: add solutions to lc problem: No.0907 #2021

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
215 changes: 140 additions & 75 deletions solution/0900-0999/0907.Sum of Subarray Minimums/README.md
View file
Original file line number Diff line number Diff line change
@@ -73,7 +73,7 @@

注意数据的溢出以及取模操作。

时间复杂度 $O(n)$，其中 $n$ 表示数组 $arr$ 的长度。
时间复杂度 $O(n)$，空间复杂度 $O(n)$。其中 $n$ 为数组 $arr$ 的长度。

<!-- tabs:start -->

@@ -138,7 +138,7 @@ class Solution {
}
stk.push(i);
}
int mod = (int) 1e9 + 7;
final int mod = (int) 1e9 + 7;
long ans = 0;
for (int i = 0; i < n; ++i) {
ans += (long) (i - left[i]) * (right[i] - i) % mod * arr[i] % mod;
@@ -152,9 +152,6 @@ class Solution {
### **C++**

```cpp
using ll = long long;
const int mod = 1e9 + 7;

class Solution {
public:
int sumSubarrayMins(vector<int>& arr) {
@@ -163,28 +160,160 @@ public:
vector<int> right(n, n);
stack<int> stk;
for (int i = 0; i < n; ++i) {
while (!stk.empty() && arr[stk.top()] >= arr[i]) stk.pop();
if (!stk.empty()) left[i] = stk.top();
while (!stk.empty() && arr[stk.top()] >= arr[i]) {
stk.pop();
}
if (!stk.empty()) {
left[i] = stk.top();
}
stk.push(i);
}
stk = stack<int>();
for (int i = n - 1; i >= 0; --i) {
while (!stk.empty() && arr[stk.top()] > arr[i]) stk.pop();
if (!stk.empty()) right[i] = stk.top();
while (!stk.empty() && arr[stk.top()] > arr[i]) {
stk.pop();
}
if (!stk.empty()) {
right[i] = stk.top();
}
stk.push(i);
}
ll ans = 0;
long long ans = 0;
const int mod = 1e9 + 7;
for (int i = 0; i < n; ++i) {
ans += (ll) (i - left[i]) * (right[i] - i) * arr[i] % mod;
ans += 1LL * (i - left[i]) * (right[i] - i) * arr[i] % mod;
ans %= mod;
}
return ans;
}
};
```

### **Go**

```go
func sumSubarrayMins(arr []int) (ans int) {
n := len(arr)
left := make([]int, n)
right := make([]int, n)
for i := range left {
left[i] = -1
right[i] = n
}
stk := []int{}
for i, v := range arr {
for len(stk) > 0 && arr[stk[len(stk)-1]] >= v {
stk = stk[:len(stk)-1]
}
if len(stk) > 0 {
left[i] = stk[len(stk)-1]
}
stk = append(stk, i)
}
stk = []int{}
for i := n - 1; i >= 0; i-- {
for len(stk) > 0 && arr[stk[len(stk)-1]] > arr[i] {
stk = stk[:len(stk)-1]
}
if len(stk) > 0 {
right[i] = stk[len(stk)-1]
}
stk = append(stk, i)
}
const mod int = 1e9 + 7
for i, v := range arr {
ans += (i - left[i]) * (right[i] - i) * v % mod
ans %= mod
}
return
}
```

### **TypeScript**

```ts
function sumSubarrayMins(arr: number[]): number {
const n: number = arr.length;
const left: number[] = Array(n).fill(-1);
const right: number[] = Array(n).fill(n);
const stk: number[] = [];
for (let i = 0; i < n; ++i) {
while (stk.length > 0 && arr[stk.at(-1)] >= arr[i]) {
stk.pop();
}
if (stk.length > 0) {
left[i] = stk.at(-1);
}
stk.push(i);
}

stk.length = 0;
for (let i = n - 1; ~i; --i) {
while (stk.length > 0 && arr[stk.at(-1)] > arr[i]) {
stk.pop();
}
if (stk.length > 0) {
right[i] = stk.at(-1);
}
stk.push(i);
}

const mod: number = 1e9 + 7;
let ans: number = 0;
for (let i = 0; i < n; ++i) {
ans += ((((i - left[i]) * (right[i] - i)) % mod) * arr[i]) % mod;
ans %= mod;
}
return ans;
}
```

### **Rust**

```rust
use std::collections::VecDeque;

impl Solution {
pub fn sum_subarray_mins(arr: Vec<i32>) -> i32 {
let n = arr.len();
let mut left = vec![-1; n];
let mut right = vec![n as i32; n];
let mut stk: VecDeque<usize> = VecDeque::new();

for i in 0..n {
while !stk.is_empty() && arr[*stk.back().unwrap()] >= arr[i] {
stk.pop_back();
}
if let Some(&top) = stk.back() {
left[i] = top as i32;
}
stk.push_back(i);
}

stk.clear();
for i in (0..n).rev() {
while !stk.is_empty() && arr[*stk.back().unwrap()] > arr[i] {
stk.pop_back();
}
if let Some(&top) = stk.back() {
right[i] = top as i32;
}
stk.push_back(i);
}

let MOD = 1_000_000_007;
let mut ans: i64 = 0;
for i in 0..n {
ans +=
((((right[i] - (i as i32)) * ((i as i32) - left[i])) as i64) * (arr[i] as i64)) %
MOD;
ans %= MOD;
}
ans as i32
}
}
```

```rust
const MOD: i64 = (1e9 as i64) + 7;

@@ -236,70 +365,6 @@ impl Solution {
}
```

### **Go**

```go
func sumSubarrayMins(arr []int) int {
mod := int(1e9) + 7
n := len(arr)
left := make([]int, n)
right := make([]int, n)
for i := range left {
left[i] = -1
right[i] = n
}
stk := []int{}
for i, v := range arr {
for len(stk) > 0 && arr[stk[len(stk)-1]] >= v {
stk = stk[:len(stk)-1]
}
if len(stk) > 0 {
left[i] = stk[len(stk)-1]
}
stk = append(stk, i)
}
stk = []int{}
for i := n - 1; i >= 0; i-- {
for len(stk) > 0 && arr[stk[len(stk)-1]] > arr[i] {
stk = stk[:len(stk)-1]
}
if len(stk) > 0 {
right[i] = stk[len(stk)-1]
}
stk = append(stk, i)
}
ans := 0
for i, v := range arr {
ans += (i - left[i]) * (right[i] - i) * v % mod
ans %= mod
}
return ans
}
```

### **TypeScript**

```ts
function sumSubarrayMins(arr: number[]): number {
const n = arr.length;
function getEle(i: number): number {
if (i == -1 || i == n) return Number.MIN_SAFE_INTEGER;
return arr[i];
}
let ans = 0;
const mod = 10 ** 9 + 7;
let stack = [];
for (let i = -1; i <= n; i++) {
while (stack.length && getEle(stack[0]) > getEle(i)) {
const idx = stack.shift();
ans = (ans + arr[idx] * (idx - stack[0]) * (i - idx)) % mod;
}
stack.unshift(i);
}
return ans;
}
```

### **...**

```
Loading