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.

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.2195 #2790

Merged
merged 1 commit into from
May 11, 2024
Merged
Show file tree
Hide file tree
Changes from all commits
Commits
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
Original file line number Diff line number Diff line change
Expand Up @@ -44,47 +44,42 @@ nums 最终元素和为 5 + 6 + 1 + 2 + 3 + 4 + 7 + 8 = 36 ,这是所有情况

### 方法一:排序 + 贪心 + 数学

我们不妨向数组中加入两个哨兵节点,分别为 $0$ 和 $2 \times 10^9$。

然后我们对数组进行排序,那么对于数组中的任意两个相邻的元素 $a$ 和 $b$,区间 $[a+1, b-1]$ 中的整数都是未出现在数组中的,我们可以将这些整数加入到数组中。

因此,我们从小到大遍历数组中的相邻元素对 $(a, b)$,对于每个相邻元素对,我们计算区间 $[a+1, b-1]$ 中的整数个数 $m$,那么这 $m$ 个整数的和为 $\frac{m \times (a+1 + a+m)}{2}$,我们将这个和累加到答案中,并将 $k$ 减去 $m$。如果 $k$ 减到 $0$,我们就可以停止遍历了,返回答案。

时间复杂度 $O(n \times \log n)$,空间复杂度 $O(\log n)$。其中 $n$ 为数组的长度。

<!-- tabs:start -->

```python
class Solution:
def minimalKSum(self, nums: List[int], k: int) -> int:
nums.append(0)
nums.append(2 * 10**9)
nums.extend([0, 2 * 10**9])
nums.sort()
ans = 0
for a, b in pairwise(nums):
n = min(k, b - a - 1)
if n <= 0:
continue
k -= n
ans += (a + 1 + a + n) * n // 2
if k == 0:
break
m = max(0, min(k, b - a - 1))
ans += (a + 1 + a + m) * m // 2
k -= m
return ans
```

```java
class Solution {
public long minimalKSum(int[] nums, int k) {
int[] arr = new int[nums.length + 2];
arr[arr.length - 1] = (int) 2e9;
for (int i = 0; i < nums.length; ++i) {
arr[i + 1] = nums[i];
}
int n = nums.length;
int[] arr = new int[n + 2];
arr[1] = 2 * 1000000000;
System.arraycopy(nums, 0, arr, 2, n);
Arrays.sort(arr);
long ans = 0;
for (int i = 1; i < arr.length; ++i) {
int a = arr[i - 1], b = arr[i];
int n = Math.min(k, b - a - 1);
if (n <= 0) {
continue;
}
k -= n;
ans += (long) (a + 1 + a + n) * n / 2;
if (k == 0) {
break;
}
for (int i = 0; i < n + 1 && k > 0; ++i) {
int m = Math.max(0, Math.min(k, arr[i + 1] - arr[i] - 1));
ans += (arr[i] + 1L + arr[i] + m) * m / 2;
k -= m;
}
return ans;
}
Expand All @@ -99,37 +94,41 @@ public:
nums.push_back(2e9);
sort(nums.begin(), nums.end());
long long ans = 0;
for (int i = 1; i < nums.size(); ++i) {
int a = nums[i - 1], b = nums[i];
int n = min(k, b - a - 1);
if (n <= 0) continue;
k -= n;
ans += 1ll * (a + 1 + a + n) * n / 2;
if (k == 0) break;
for (int i = 0; i < nums.size() - 1 && k > 0; ++i) {
int m = max(0, min(k, nums[i + 1] - nums[i] - 1));
ans += 1LL * (nums[i] + 1 + nums[i] + m) * m / 2;
k -= m;
}
return ans;
}
};
```

```go
func minimalKSum(nums []int, k int) int64 {
nums = append(nums, 0, 2e9)
func minimalKSum(nums []int, k int) (ans int64) {
nums = append(nums, []int{0, 2e9}...)
sort.Ints(nums)
ans := 0
for i := 1; i < len(nums); i++ {
a, b := nums[i-1], nums[i]
n := min(k, b-a-1)
if n <= 0 {
continue
}
k -= n
ans += (a + 1 + a + n) * n / 2
if k == 0 {
break
}
for i, b := range nums[1:] {
a := nums[i]
m := max(0, min(k, b-a-1))
ans += int64(a+1+a+m) * int64(m) / 2
k -= m
}
return int64(ans)
return ans
}
```

```ts
function minimalKSum(nums: number[], k: number): number {
nums.push(...[0, 2 * 10 ** 9]);
nums.sort((a, b) => a - b);
let ans = 0;
for (let i = 0; i < nums.length - 1; ++i) {
const m = Math.max(0, Math.min(k, nums[i + 1] - nums[i] - 1));
ans += Number((BigInt(nums[i] + 1 + nums[i] + m) * BigInt(m)) / BigInt(2));
k -= m;
}
return ans;
}
```

Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -41,49 +41,44 @@ The sum of the six integers appended is 1 + 2 + 3 + 4 + 7 + 8 = 25, so we return

## Solutions

### Solution 1
### Solution 1: Sorting + Greedy + Mathematics

We can add two sentinel nodes to the array, which are $0$ and $2 \times 10^9$.

Then we sort the array. For any two adjacent elements $a$ and $b$ in the array, the integers in the interval $[a+1, b-1]$ do not appear in the array, and we can add these integers to the array.

Therefore, we traverse the adjacent element pairs $(a, b)$ in the array from small to large. For each adjacent element pair, we calculate the number of integers $m$ in the interval $[a+1, b-1]$. The sum of these $m$ integers is $\frac{m \times (a+1 + a+m)}{2}$. We add this sum to the answer and subtract $m$ from $k$. If $k$ is reduced to $0$, we can stop the traversal and return the answer.

The time complexity is $O(n \times \log n)$, and the space complexity is $O(\log n)$. Where $n$ is the length of the array.

<!-- tabs:start -->

```python
class Solution:
def minimalKSum(self, nums: List[int], k: int) -> int:
nums.append(0)
nums.append(2 * 10**9)
nums.extend([0, 2 * 10**9])
nums.sort()
ans = 0
for a, b in pairwise(nums):
n = min(k, b - a - 1)
if n <= 0:
continue
k -= n
ans += (a + 1 + a + n) * n // 2
if k == 0:
break
m = max(0, min(k, b - a - 1))
ans += (a + 1 + a + m) * m // 2
k -= m
return ans
```

```java
class Solution {
public long minimalKSum(int[] nums, int k) {
int[] arr = new int[nums.length + 2];
arr[arr.length - 1] = (int) 2e9;
for (int i = 0; i < nums.length; ++i) {
arr[i + 1] = nums[i];
}
int n = nums.length;
int[] arr = new int[n + 2];
arr[1] = 2 * 1000000000;
System.arraycopy(nums, 0, arr, 2, n);
Arrays.sort(arr);
long ans = 0;
for (int i = 1; i < arr.length; ++i) {
int a = arr[i - 1], b = arr[i];
int n = Math.min(k, b - a - 1);
if (n <= 0) {
continue;
}
k -= n;
ans += (long) (a + 1 + a + n) * n / 2;
if (k == 0) {
break;
}
for (int i = 0; i < n + 1 && k > 0; ++i) {
int m = Math.max(0, Math.min(k, arr[i + 1] - arr[i] - 1));
ans += (arr[i] + 1L + arr[i] + m) * m / 2;
k -= m;
}
return ans;
}
Expand All @@ -98,37 +93,41 @@ public:
nums.push_back(2e9);
sort(nums.begin(), nums.end());
long long ans = 0;
for (int i = 1; i < nums.size(); ++i) {
int a = nums[i - 1], b = nums[i];
int n = min(k, b - a - 1);
if (n <= 0) continue;
k -= n;
ans += 1ll * (a + 1 + a + n) * n / 2;
if (k == 0) break;
for (int i = 0; i < nums.size() - 1 && k > 0; ++i) {
int m = max(0, min(k, nums[i + 1] - nums[i] - 1));
ans += 1LL * (nums[i] + 1 + nums[i] + m) * m / 2;
k -= m;
}
return ans;
}
};
```

```go
func minimalKSum(nums []int, k int) int64 {
nums = append(nums, 0, 2e9)
func minimalKSum(nums []int, k int) (ans int64) {
nums = append(nums, []int{0, 2e9}...)
sort.Ints(nums)
ans := 0
for i := 1; i < len(nums); i++ {
a, b := nums[i-1], nums[i]
n := min(k, b-a-1)
if n <= 0 {
continue
}
k -= n
ans += (a + 1 + a + n) * n / 2
if k == 0 {
break
}
for i, b := range nums[1:] {
a := nums[i]
m := max(0, min(k, b-a-1))
ans += int64(a+1+a+m) * int64(m) / 2
k -= m
}
return int64(ans)
return ans
}
```

```ts
function minimalKSum(nums: number[], k: number): number {
nums.push(...[0, 2 * 10 ** 9]);
nums.sort((a, b) => a - b);
let ans = 0;
for (let i = 0; i < nums.length - 1; ++i) {
const m = Math.max(0, Math.min(k, nums[i + 1] - nums[i] - 1));
ans += Number((BigInt(nums[i] + 1 + nums[i] + m) * BigInt(m)) / BigInt(2));
k -= m;
}
return ans;
}
```

Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -5,13 +5,10 @@ class Solution {
nums.push_back(2e9);
sort(nums.begin(), nums.end());
long long ans = 0;
for (int i = 1; i < nums.size(); ++i) {
int a = nums[i - 1], b = nums[i];
int n = min(k, b - a - 1);
if (n <= 0) continue;
k -= n;
ans += 1ll * (a + 1 + a + n) * n / 2;
if (k == 0) break;
for (int i = 0; i < nums.size() - 1 && k > 0; ++i) {
int m = max(0, min(k, nums[i + 1] - nums[i] - 1));
ans += 1LL * (nums[i] + 1 + nums[i] + m) * m / 2;
k -= m;
}
return ans;
}
Expand Down
Original file line number Diff line number Diff line change
@@ -1,18 +1,11 @@
func minimalKSum(nums []int, k int) int64 {
nums = append(nums, 0, 2e9)
func minimalKSum(nums []int, k int) (ans int64) {
nums = append(nums, []int{0, 2e9}...)
sort.Ints(nums)
ans := 0
for i := 1; i < len(nums); i++ {
a, b := nums[i-1], nums[i]
n := min(k, b-a-1)
if n <= 0 {
continue
}
k -= n
ans += (a + 1 + a + n) * n / 2
if k == 0 {
break
}
for i, b := range nums[1:] {
a := nums[i]
m := max(0, min(k, b-a-1))
ans += int64(a+1+a+m) * int64(m) / 2
k -= m
}
return int64(ans)
return ans
}
Original file line number Diff line number Diff line change
@@ -1,23 +1,15 @@
class Solution {
public long minimalKSum(int[] nums, int k) {
int[] arr = new int[nums.length + 2];
arr[arr.length - 1] = (int) 2e9;
for (int i = 0; i < nums.length; ++i) {
arr[i + 1] = nums[i];
}
int n = nums.length;
int[] arr = new int[n + 2];
arr[1] = 2 * 1000000000;
System.arraycopy(nums, 0, arr, 2, n);
Arrays.sort(arr);
long ans = 0;
for (int i = 1; i < arr.length; ++i) {
int a = arr[i - 1], b = arr[i];
int n = Math.min(k, b - a - 1);
if (n <= 0) {
continue;
}
k -= n;
ans += (long) (a + 1 + a + n) * n / 2;
if (k == 0) {
break;
}
for (int i = 0; i < n + 1 && k > 0; ++i) {
int m = Math.max(0, Math.min(k, arr[i + 1] - arr[i] - 1));
ans += (arr[i] + 1L + arr[i] + m) * m / 2;
k -= m;
}
return ans;
}
Expand Down
Original file line number Diff line number Diff line change
@@ -1,15 +1,10 @@
class Solution:
def minimalKSum(self, nums: List[int], k: int) -> int:
nums.append(0)
nums.append(2 * 10**9)
nums.extend([0, 2 * 10**9])
nums.sort()
ans = 0
for a, b in pairwise(nums):
n = min(k, b - a - 1)
if n <= 0:
continue
k -= n
ans += (a + 1 + a + n) * n // 2
if k == 0:
break
m = max(0, min(k, b - a - 1))
ans += (a + 1 + a + m) * m // 2
k -= m
return ans
Original file line number Diff line number Diff line change
@@ -0,0 +1,11 @@
function minimalKSum(nums: number[], k: number): number {
nums.push(...[0, 2 * 10 ** 9]);
nums.sort((a, b) => a - b);
let ans = 0;
for (let i = 0; i < nums.length - 1; ++i) {
const m = Math.max(0, Math.min(k, nums[i + 1] - nums[i] - 1));
ans += Number((BigInt(nums[i] + 1 + nums[i] + m) * BigInt(m)) / BigInt(2));
k -= m;
}
return ans;
}
Loading