# leetcode contest 54 solution

• 696. Count Binary Substrings
• 697. Degree of an Array
• 698. Partition to K Equal Sum Subsets
• 699. Falling Squares

### 696. Count Binary Substrings

Give a string `s`, count the number of non-empty (contiguous) substrings that have the same number of 0’s and 1’s, and all the 0’s and all the 1’s in these substrings are grouped consecutively.

Substrings that occur multiple times are counted the number of times they occur.

Example 1:

Example 2:

Note:

• `s.length` will be between 1 and 50,000.
• `s` will only consist of “0” or “1” characters.

Python

### 697. Degree of an Array

Given a non-empty array of non-negative integers `nums`, the degree of this array is defined as the maximum frequency of any one of its elements.

Your task is to find the smallest possible length of a (contiguous) subarray of `nums`, that has the same degree as `nums`.

Example 1:

Example 2:

Note:

• `nums.length` will be between 1 and 50,000.
• `nums[i]` will be an integer between 0 and 49,999.

Python

### 698. Partition to K Equal Sum Subsets

Given an array of integers `nums` and a positive integer `k`, find whether it’s possible to divide this array into `k`non-empty subsets whose sums are all equal.

Example 1:

Note:

• `1 <= k <= len(nums) <= 16`.
• `0 < nums[i] < 10000`.

Java

### 699. Falling Squares

On an infinite number line (x-axis), we drop given squares in the order they are given.

The `i`-th square dropped (`positions[i] = (left, side_length)`) is a square with the left-most point being `positions[i][0]` and sidelength `positions[i][1]`.

The square is dropped with the bottom edge parallel to the number line, and from a higher height than all currently landed squares. We wait for each square to stick before dropping the next.

The squares are infinitely sticky on their bottom edge, and will remain fixed to any positive length surface they touch (either the number line or another square). Squares dropped adjacent to each other will not stick together prematurely.

Return a list `ans` of heights. Each height `ans[i]` represents the current highest height of any square we have dropped, after dropping squares represented by `positions[0], positions[1], ..., positions[i]`.

Example 1:

After the first drop of ```positions[0] = [1, 2]: _aa _aa ------- ```The maximum height of any square is 2.

After the second drop of ```positions[1] = [2, 3]: __aaa __aaa __aaa _aa__ _aa__ -------------- ```The maximum height of any square is 5. The larger square stays on top of the smaller square despite where its center of gravity is, because squares are infinitely sticky on their bottom edge.

After the third drop of ```positions[1] = [6, 1]: __aaa __aaa __aaa _aa _aa___a -------------- ```The maximum height of any square is still 5. Thus, we return an answer of `[2, 5, 5]`.

Example 2:

Note:

• `1 <= positions.length <= 1000`.
• `1 <= positions[0] <= 10^8`.
• `1 <= positions[1] <= 10^6`.

RMQ问题，并且是设置值的RMQ。

C++

Python

• 696. Count Binary Substrings
• 697. Degree of an Array
• 698. Partition to K Equal Sum Subsets
• 699. Falling Squares