diff --git a/solution/1500-1599/1508.Range Sum of Sorted Subarray Sums/README.md b/solution/1500-1599/1508.Range Sum of Sorted Subarray Sums/README.md index 25286920cca4f..41a8792547f05 100644 --- a/solution/1500-1599/1508.Range Sum of Sorted Subarray Sums/README.md +++ b/solution/1500-1599/1508.Range Sum of Sorted Subarray Sums/README.md @@ -31,7 +31,7 @@ tags: 
 输入：nums = [1,2,3,4], n = 4, left = 1, right = 5
-输出：13 
+输出：13
 解释：所有的子数组和为 1, 3, 6, 10, 2, 5, 9, 3, 7, 4 。将它们升序排序后，我们得到新的数组 [1, 2, 3, 3, 4, 5, 6, 7, 9, 10] 。下标从 le = 1 到 ri = 5 的和为 1 + 2 + 3 + 3 + 4 = 13 。
@@ -67,11 +67,11 @@ tags: -### 方法一：排序 +### 方法一：模拟 -按照题意生成 `arr` 数组，排序后，对 $[left-1,.. right-1]$ 范围的所有元素求和，得到结果。 +我们可以按照题目的要求，生成数组 $\textit{arr}$，然后对数组进行排序，最后求出 $[\textit{left}-1, \textit{right}-1]$ 范围的所有元素的和，得到结果。 -时间复杂度 $O(n^2\log n)$，空间复杂度 $O(n^2)$。其中 $n$ 为题目给定的数组长度。 +时间复杂度 $O(n^2 \times \log n)$，空间复杂度 $O(n^2)$。其中 $n$ 为题目给定的数组长度。 @@ -175,13 +175,8 @@ function rangeSum(nums: number[], n: number, left: number, right: number): numbe } } - let ans = 0; arr = arr.sort((a, b) => a - b).slice(left - 1, right); - for (const x of arr) { - ans += x; - } - - return ans % mod; + return arr.reduce((acc, cur) => (acc + cur) % mod, 0); } ``` @@ -199,13 +194,8 @@ function rangeSum(nums, n, left, right) { } } - let ans = 0; arr = arr.sort((a, b) => a - b).slice(left - 1, right); - for (const x of arr) { - ans += x; - } - - return ans % mod; + return arr.reduce((acc, cur) => acc + cur, 0) % mod; } ``` diff --git a/solution/1500-1599/1508.Range Sum of Sorted Subarray Sums/README_EN.md b/solution/1500-1599/1508.Range Sum of Sorted Subarray Sums/README_EN.md index 6645ba6d28c43..c11ebd6eecc33 100644 --- a/solution/1500-1599/1508.Range Sum of Sorted Subarray Sums/README_EN.md +++ b/solution/1500-1599/1508.Range Sum of Sorted Subarray Sums/README_EN.md @@ -30,8 +30,8 @@ tags: 
 Input: nums = [1,2,3,4], n = 4, left = 1, right = 5
-Output: 13 
-Explanation: All subarray sums are 1, 3, 6, 10, 2, 5, 9, 3, 7, 4. After sorting them in non-decreasing order we have the new array [1, 2, 3, 3, 4, 5, 6, 7, 9, 10]. The sum of the numbers from index le = 1 to ri = 5 is 1 + 2 + 3 + 3 + 4 = 13. 
+Output: 13
+Explanation: All subarray sums are 1, 3, 6, 10, 2, 5, 9, 3, 7, 4. After sorting them in non-decreasing order we have the new array [1, 2, 3, 3, 4, 5, 6, 7, 9, 10]. The sum of the numbers from index le = 1 to ri = 5 is 1 + 2 + 3 + 3 + 4 = 13.

Example 2:

@@ -65,11 +65,11 @@ tags: -### Solution 1: Sorting +### Solution 1: Simulation -According to the problem statement, generate the `arr` array, sort it, and then sum all the elements in the range $[left-1,.. right-1]$ to get the result. +We can generate the array $\textit{arr}$ according to the problem's requirements, then sort the array, and finally calculate the sum of all elements in the range $[\textit{left}-1, \textit{right}-1]$ to get the result. -Time complexity is $O(n^2 \times \log n)$, and space complexity is $O(n^2)$. Here, $n$ is the length of the array given in the problem. +The time complexity is $O(n^2 \times \log n)$, and the space complexity is $O(n^2)$. Here, $n$ is the length of the array given in the problem. @@ -173,13 +173,8 @@ function rangeSum(nums: number[], n: number, left: number, right: number): numbe } } - let ans = 0; arr = arr.sort((a, b) => a - b).slice(left - 1, right); - for (const x of arr) { - ans += x; - } - - return ans % mod; + return arr.reduce((acc, cur) => (acc + cur) % mod, 0); } ``` @@ -197,13 +192,8 @@ function rangeSum(nums, n, left, right) { } } - let ans = 0; arr = arr.sort((a, b) => a - b).slice(left - 1, right); - for (const x of arr) { - ans += x; - } - - return ans % mod; + return arr.reduce((acc, cur) => acc + cur, 0) % mod; } ``` diff --git a/solution/1500-1599/1508.Range Sum of Sorted Subarray Sums/Solution.js b/solution/1500-1599/1508.Range Sum of Sorted Subarray Sums/Solution.js index 83f07fdce38b7..ee496cb207c08 100644 --- a/solution/1500-1599/1508.Range Sum of Sorted Subarray Sums/Solution.js +++ b/solution/1500-1599/1508.Range Sum of Sorted Subarray Sums/Solution.js @@ -9,11 +9,6 @@ function rangeSum(nums, n, left, right) { } } - let ans = 0; arr = arr.sort((a, b) => a - b).slice(left - 1, right); - for (const x of arr) { - ans += x; - } - - return ans % mod; + return arr.reduce((acc, cur) => acc + cur, 0) % mod; } diff --git a/solution/1500-1599/1508.Range Sum of Sorted Subarray Sums/Solution.ts b/solution/1500-1599/1508.Range Sum of Sorted Subarray Sums/Solution.ts index 22e1796afe0a9..22dd44876b7e5 100644 --- a/solution/1500-1599/1508.Range Sum of Sorted Subarray Sums/Solution.ts +++ b/solution/1500-1599/1508.Range Sum of Sorted Subarray Sums/Solution.ts @@ -9,11 +9,6 @@ function rangeSum(nums: number[], n: number, left: number, right: number): numbe } } - let ans = 0; arr = arr.sort((a, b) => a - b).slice(left - 1, right); - for (const x of arr) { - ans += x; - } - - return ans % mod; + return arr.reduce((acc, cur) => (acc + cur) % mod, 0); } diff --git a/solution/1500-1599/1512.Number of Good Pairs/README.md b/solution/1500-1599/1512.Number of Good Pairs/README.md index be1308541d89b..275710512ae47 100644 --- a/solution/1500-1599/1512.Number of Good Pairs/README.md +++ b/solution/1500-1599/1512.Number of Good Pairs/README.md @@ -132,7 +132,7 @@ func numIdenticalPairs(nums []int) (ans int) { ```ts function numIdenticalPairs(nums: number[]): number { - const cnt = new Array(101).fill(0); + const cnt: number[] = Array(101).fill(0); let ans = 0; for (const x of nums) { ans += cnt[x]++; @@ -146,17 +146,34 @@ function numIdenticalPairs(nums: number[]): number { ```rust impl Solution { pub fn num_identical_pairs(nums: Vec) -> i32 { - let mut cnt = [0; 101]; let mut ans = 0; - for &num in nums.iter() { - ans += cnt[num as usize]; - cnt[num as usize] += 1; + let mut cnt = [0; 101]; + for &x in nums.iter() { + ans += cnt[x as usize]; + cnt[x as usize] += 1; } ans } } ``` +#### JavaScript + +```js +/** + * @param {number[]} nums + * @return {number} + */ +var numIdenticalPairs = function (nums) { + const cnt = Array(101).fill(0); + let ans = 0; + for (const x of nums) { + ans += cnt[x]++; + } + return ans; +}; +``` + #### PHP ```php @@ -166,15 +183,12 @@ class Solution { * @return Integer */ function numIdenticalPairs($nums) { - $arr = array_values(array_unique($nums)); - for ($i = 0; $i < count($nums); $i++) { - $v[$nums[$i]] += 1; + $ans = 0; + $cnt = array_fill(0, 101, 0); + foreach ($nums as $x) { + $ans += $cnt[$x]++; } - $rs = 0; - for ($j = 0; $j < count($arr); $j++) { - $rs += ($v[$arr[$j]] * ($v[$arr[$j]] - 1)) / 2; - } - return $rs; + return $ans; } } ``` @@ -196,125 +210,4 @@ int numIdenticalPairs(int* nums, int numsSize) { - - -### 方法二 - - - -#### Python3 - -```python -class Solution: - def numIdenticalPairs(self, nums: List[int]) -> int: - cnt = Counter(nums) - return sum(v * (v - 1) for v in cnt.values()) >> 1 -``` - -#### Java - -```java -class Solution { - public int numIdenticalPairs(int[] nums) { - int[] cnt = new int[101]; - for (int x : nums) { - ++cnt[x]; - } - int ans = 0; - for (int v : cnt) { - ans += v * (v - 1) / 2; - } - return ans; - } -} -``` - -#### C++ - -```cpp -class Solution { -public: - int numIdenticalPairs(vector& nums) { - int cnt[101]{}; - for (int& x : nums) { - ++cnt[x]; - } - int ans = 0; - for (int v : cnt) { - ans += v * (v - 1) / 2; - } - return ans; - } -}; -``` - -#### Go - -```go -func numIdenticalPairs(nums []int) (ans int) { - cnt := [101]int{} - for _, x := range nums { - cnt[x]++ - } - for _, v := range cnt { - ans += v * (v - 1) / 2 - } - return -} -``` - -#### TypeScript - -```ts -function numIdenticalPairs(nums: number[]): number { - const cnt = new Array(101).fill(0); - for (const x of nums) { - ++cnt[x]; - } - let ans = 0; - for (const v of cnt) { - ans += v * (v - 1); - } - return ans >> 1; -} -``` - -#### Rust - -```rust -impl Solution { - pub fn num_identical_pairs(nums: Vec) -> i32 { - let mut cnt = [0; 101]; - for &num in nums.iter() { - cnt[num as usize] += 1; - } - let mut ans = 0; - for &v in cnt.iter() { - ans += (v * (v - 1)) / 2; - } - ans - } -} -``` - -#### C - -```c -int numIdenticalPairs(int* nums, int numsSize) { - int cnt[101] = {0}; - for (int i = 0; i < numsSize; i++) { - cnt[nums[i]]++; - } - int ans = 0; - for (int i = 0; i < 101; ++i) { - ans += cnt[i] * (cnt[i] - 1) / 2; - } - return ans; -} -``` - - - - - diff --git a/solution/1500-1599/1512.Number of Good Pairs/README_EN.md b/solution/1500-1599/1512.Number of Good Pairs/README_EN.md index 5a33e5d94f4cf..ff295f5cb6171 100644 --- a/solution/1500-1599/1512.Number of Good Pairs/README_EN.md +++ b/solution/1500-1599/1512.Number of Good Pairs/README_EN.md @@ -63,7 +63,11 @@ tags: -### Solution 1 +### Solution 1: Counting + +Traverse the array, and for each element $x$, count how many elements before it are equal to $x$. This count represents the number of good pairs formed by $x$ and the previous elements. After traversing the entire array, we obtain the answer. + +The time complexity is $O(n)$, and the space complexity is $O(C)$. Here, $n$ is the length of the array, and $C$ is the range of values in the array. In this problem, $C = 101$. @@ -128,7 +132,7 @@ func numIdenticalPairs(nums []int) (ans int) { ```ts function numIdenticalPairs(nums: number[]): number { - const cnt = new Array(101).fill(0); + const cnt: number[] = Array(101).fill(0); let ans = 0; for (const x of nums) { ans += cnt[x]++; @@ -142,17 +146,34 @@ function numIdenticalPairs(nums: number[]): number { ```rust impl Solution { pub fn num_identical_pairs(nums: Vec) -> i32 { - let mut cnt = [0; 101]; let mut ans = 0; - for &num in nums.iter() { - ans += cnt[num as usize]; - cnt[num as usize] += 1; + let mut cnt = [0; 101]; + for &x in nums.iter() { + ans += cnt[x as usize]; + cnt[x as usize] += 1; } ans } } ``` +#### JavaScript + +```js +/** + * @param {number[]} nums + * @return {number} + */ +var numIdenticalPairs = function (nums) { + const cnt = Array(101).fill(0); + let ans = 0; + for (const x of nums) { + ans += cnt[x]++; + } + return ans; +}; +``` + #### PHP ```php @@ -162,15 +183,12 @@ class Solution { * @return Integer */ function numIdenticalPairs($nums) { - $arr = array_values(array_unique($nums)); - for ($i = 0; $i < count($nums); $i++) { - $v[$nums[$i]] += 1; - } - $rs = 0; - for ($j = 0; $j < count($arr); $j++) { - $rs += ($v[$arr[$j]] * ($v[$arr[$j]] - 1)) / 2; + $ans = 0; + $cnt = array_fill(0, 101, 0); + foreach ($nums as $x) { + $ans += $cnt[$x]++; } - return $rs; + return $ans; } } ``` @@ -192,125 +210,4 @@ int numIdenticalPairs(int* nums, int numsSize) { - - -### Solution 2 - - - -#### Python3 - -```python -class Solution: - def numIdenticalPairs(self, nums: List[int]) -> int: - cnt = Counter(nums) - return sum(v * (v - 1) for v in cnt.values()) >> 1 -``` - -#### Java - -```java -class Solution { - public int numIdenticalPairs(int[] nums) { - int[] cnt = new int[101]; - for (int x : nums) { - ++cnt[x]; - } - int ans = 0; - for (int v : cnt) { - ans += v * (v - 1) / 2; - } - return ans; - } -} -``` - -#### C++ - -```cpp -class Solution { -public: - int numIdenticalPairs(vector& nums) { - int cnt[101]{}; - for (int& x : nums) { - ++cnt[x]; - } - int ans = 0; - for (int v : cnt) { - ans += v * (v - 1) / 2; - } - return ans; - } -}; -``` - -#### Go - -```go -func numIdenticalPairs(nums []int) (ans int) { - cnt := [101]int{} - for _, x := range nums { - cnt[x]++ - } - for _, v := range cnt { - ans += v * (v - 1) / 2 - } - return -} -``` - -#### TypeScript - -```ts -function numIdenticalPairs(nums: number[]): number { - const cnt = new Array(101).fill(0); - for (const x of nums) { - ++cnt[x]; - } - let ans = 0; - for (const v of cnt) { - ans += v * (v - 1); - } - return ans >> 1; -} -``` - -#### Rust - -```rust -impl Solution { - pub fn num_identical_pairs(nums: Vec) -> i32 { - let mut cnt = [0; 101]; - for &num in nums.iter() { - cnt[num as usize] += 1; - } - let mut ans = 0; - for &v in cnt.iter() { - ans += (v * (v - 1)) / 2; - } - ans - } -} -``` - -#### C - -```c -int numIdenticalPairs(int* nums, int numsSize) { - int cnt[101] = {0}; - for (int i = 0; i < numsSize; i++) { - cnt[nums[i]]++; - } - int ans = 0; - for (int i = 0; i < 101; ++i) { - ans += cnt[i] * (cnt[i] - 1) / 2; - } - return ans; -} -``` - - - - - diff --git a/solution/1500-1599/1512.Number of Good Pairs/Solution.js b/solution/1500-1599/1512.Number of Good Pairs/Solution.js new file mode 100644 index 0000000000000..e4586ffdc80e5 --- /dev/null +++ b/solution/1500-1599/1512.Number of Good Pairs/Solution.js @@ -0,0 +1,12 @@ +/** + * @param {number[]} nums + * @return {number} + */ +var numIdenticalPairs = function (nums) { + const cnt = Array(101).fill(0); + let ans = 0; + for (const x of nums) { + ans += cnt[x]++; + } + return ans; +}; diff --git a/solution/1500-1599/1512.Number of Good Pairs/Solution.rs b/solution/1500-1599/1512.Number of Good Pairs/Solution.rs index 2d6329d025e37..c9e69ccc66d6c 100644 --- a/solution/1500-1599/1512.Number of Good Pairs/Solution.rs +++ b/solution/1500-1599/1512.Number of Good Pairs/Solution.rs @@ -1,10 +1,10 @@ impl Solution { pub fn num_identical_pairs(nums: Vec) -> i32 { - let mut cnt = [0; 101]; let mut ans = 0; - for &num in nums.iter() { - ans += cnt[num as usize]; - cnt[num as usize] += 1; + let mut cnt = [0; 101]; + for &x in nums.iter() { + ans += cnt[x as usize]; + cnt[x as usize] += 1; } ans } diff --git a/solution/1500-1599/1512.Number of Good Pairs/Solution.ts b/solution/1500-1599/1512.Number of Good Pairs/Solution.ts index e48f9b86d8735..8b13f5f86d0a5 100644 --- a/solution/1500-1599/1512.Number of Good Pairs/Solution.ts +++ b/solution/1500-1599/1512.Number of Good Pairs/Solution.ts @@ -1,5 +1,5 @@ function numIdenticalPairs(nums: number[]): number { - const cnt = new Array(101).fill(0); + const cnt: number[] = Array(101).fill(0); let ans = 0; for (const x of nums) { ans += cnt[x]++; diff --git a/solution/1500-1599/1512.Number of Good Pairs/Solution2.c b/solution/1500-1599/1512.Number of Good Pairs/Solution2.c deleted file mode 100644 index a15ad28a7ed56..0000000000000 --- a/solution/1500-1599/1512.Number of Good Pairs/Solution2.c +++ /dev/null @@ -1,11 +0,0 @@ -int numIdenticalPairs(int* nums, int numsSize) { - int cnt[101] = {0}; - for (int i = 0; i < numsSize; i++) { - cnt[nums[i]]++; - } - int ans = 0; - for (int i = 0; i < 101; ++i) { - ans += cnt[i] * (cnt[i] - 1) / 2; - } - return ans; -} \ No newline at end of file diff --git a/solution/1500-1599/1512.Number of Good Pairs/Solution2.cpp b/solution/1500-1599/1512.Number of Good Pairs/Solution2.cpp deleted file mode 100644 index eee7d0bca33b1..0000000000000 --- a/solution/1500-1599/1512.Number of Good Pairs/Solution2.cpp +++ /dev/null @@ -1,14 +0,0 @@ -class Solution { -public: - int numIdenticalPairs(vector& nums) { - int cnt[101]{}; - for (int& x : nums) { - ++cnt[x]; - } - int ans = 0; - for (int v : cnt) { - ans += v * (v - 1) / 2; - } - return ans; - } -}; \ No newline at end of file diff --git a/solution/1500-1599/1512.Number of Good Pairs/Solution2.go b/solution/1500-1599/1512.Number of Good Pairs/Solution2.go deleted file mode 100644 index 9221177f22a7d..0000000000000 --- a/solution/1500-1599/1512.Number of Good Pairs/Solution2.go +++ /dev/null @@ -1,10 +0,0 @@ -func numIdenticalPairs(nums []int) (ans int) { - cnt := [101]int{} - for _, x := range nums { - cnt[x]++ - } - for _, v := range cnt { - ans += v * (v - 1) / 2 - } - return -} \ No newline at end of file diff --git a/solution/1500-1599/1512.Number of Good Pairs/Solution2.java b/solution/1500-1599/1512.Number of Good Pairs/Solution2.java deleted file mode 100644 index ded87607f2db9..0000000000000 --- a/solution/1500-1599/1512.Number of Good Pairs/Solution2.java +++ /dev/null @@ -1,13 +0,0 @@ -class Solution { - public int numIdenticalPairs(int[] nums) { - int[] cnt = new int[101]; - for (int x : nums) { - ++cnt[x]; - } - int ans = 0; - for (int v : cnt) { - ans += v * (v - 1) / 2; - } - return ans; - } -} \ No newline at end of file diff --git a/solution/1500-1599/1512.Number of Good Pairs/Solution2.py b/solution/1500-1599/1512.Number of Good Pairs/Solution2.py deleted file mode 100644 index fd0d38656d18d..0000000000000 --- a/solution/1500-1599/1512.Number of Good Pairs/Solution2.py +++ /dev/null @@ -1,4 +0,0 @@ -class Solution: - def numIdenticalPairs(self, nums: List[int]) -> int: - cnt = Counter(nums) - return sum(v * (v - 1) for v in cnt.values()) >> 1 diff --git a/solution/1500-1599/1512.Number of Good Pairs/Solution2.rs b/solution/1500-1599/1512.Number of Good Pairs/Solution2.rs deleted file mode 100644 index 555ad4f47400f..0000000000000 --- a/solution/1500-1599/1512.Number of Good Pairs/Solution2.rs +++ /dev/null @@ -1,13 +0,0 @@ -impl Solution { - pub fn num_identical_pairs(nums: Vec) -> i32 { - let mut cnt = [0; 101]; - for &num in nums.iter() { - cnt[num as usize] += 1; - } - let mut ans = 0; - for &v in cnt.iter() { - ans += (v * (v - 1)) / 2; - } - ans - } -} diff --git a/solution/1500-1599/1512.Number of Good Pairs/Solution2.ts b/solution/1500-1599/1512.Number of Good Pairs/Solution2.ts deleted file mode 100644 index bf835619d39e1..0000000000000 --- a/solution/1500-1599/1512.Number of Good Pairs/Solution2.ts +++ /dev/null @@ -1,11 +0,0 @@ -function numIdenticalPairs(nums: number[]): number { - const cnt = new Array(101).fill(0); - for (const x of nums) { - ++cnt[x]; - } - let ans = 0; - for (const v of cnt) { - ans += v * (v - 1); - } - return ans >> 1; -}