## Hypercube's LeetCode Weekly Contest 53

- Rank:
**334**/ 2932 - Score: 15 / 24
- Finish Time: 00:55:20

### Binary Number with Alternating Bits

Given a positive integer, check whether it has alternating bits or not.

**Example 1:**

```
Input: 5
Output: True
Explanation:
The binary representation of 5 is: 101
```

**Example 2:**

```
Input: 7
Output: False
Explanation:
The binary representation of 7 is: 111
```

**Accepted**in 00:07:48 with 1 wrong submissions

### Max Area of Island

Given a non-empty 2D array `grid`

of 0’s and 1’s, an **island** is a group of `1`

’s (representing land) connected 4-directionally (horizontal or vertical.) You may assume all four edges of the grid are surrounded by water.

Find the maximum area of an island in the given 2D array. (If there is no island, the maximum area is 0.)

**Example 1:**

```
[[0,0,1,0,0,0,0,1,0,0,0,0,0],
[0,0,0,0,0,0,0,1,1,1,0,0,0],
[0,1,1,0,1,0,0,0,0,0,0,0,0],
[0,1,0,0,1,1,0,0,1,0,1,0,0],
[0,1,0,0,1,1,0,0,1,1,1,0,0],
[0,0,0,0,0,0,0,0,0,0,1,0,0],
[0,0,0,0,0,0,0,1,1,1,0,0,0],
[0,0,0,0,0,0,0,1,1,0,0,0,0]]
```

Given the above grid, return `6`

. Note the answer is not 11, because the island must be connected 4-directionally.

**Example 2:**

```
[[0,0,0,0,0,0,0,0]]
```

Given the above grid, return `0`

.

**Note:** The length of each dimension in the given `grid`

does not exceed 50.

**Accepted**in 00:45:20

### Number of Distinct Islands

Given a non-empty 2D array `grid`

of 0’s and 1’s, an **island** is a group of `1`

’s (representing land) connected 4-directionally (horizontal or vertical.) You may assume all four edges of the grid are surrounded by water.

Count the number of **distinct** islands. An island is considered to be the same as another if and only if one island can be translated (and not rotated or reflected) to equal the other.

**Example 1:**

```
11000
11000
00011
00011
```

Given the above grid map, return `1`

.

**Example 2:**

```
11011
10000
00001
11011
```

Given the above grid map, return `3`

.

Notice that: 11 1 and 1 11 are considered different island shapes, because we do not consider reflection / rotation.

**Note:** The length of each dimension in the given `grid`

does not exceed 50.

**Accepted**in 00:43:35 with 1 wrong submissions

### Stickers to Spell Word

We are given N different types of stickers. Each sticker has a lowercase English word on it.

You would like to spell out the given `target`

string by cutting individual letters from your collection of stickers and rearranging them.

You can use each sticker more than once if you want, and you have infinite quantities of each sticker.

What is the minimum number of stickers that you need to spell out the `target`

? If the task is impossible, return -1.

**Example 1:**

Input:

```
["with", "example", "science"], "thehat"
```

Output:

```
3
```

Explanation:

```
We can use 2 "with" stickers, and 1 "example" sticker.
After cutting and rearrange the letters of those stickers, we can form the target "thehat".
Also, this is the minimum number of stickers necessary to form the target string.
```

**Example 2:**

Input:

```
["notice", "possible"], "basicbasic"
```

Output:

```
-1
```

Explanation:

```
We can't form the target "basicbasic" from cutting letters from the given stickers.
```

**Note:**

`stickers`

has length in the range`[1, 50]`

.`stickers`

consists of lowercase English words (without apostrophes).`target`

has length in the range`[1, 15]`

, and consists of lowercase English letters.- In all test cases, all words were chosen
**randomly**from the 1000 most common US English words, and the target was chosen as a concatenation of two random words. - The time limit may be more challenging than usual. It is expected that a 50 sticker test case can be solved within 35ms on average.

**Wrong Answer**