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g3201_3300.s3245_alternating_groups_iii.readme.md Maven / Gradle / Ivy

3245\. Alternating Groups III

Hard

There are some red and blue tiles arranged circularly. You are given an array of integers `colors` and a 2D integers array `queries`.

The color of tile `i` is represented by `colors[i]`:

*   `colors[i] == 0` means that tile `i` is **red**.
*   `colors[i] == 1` means that tile `i` is **blue**.

An **alternating** group is a contiguous subset of tiles in the circle with **alternating** colors (each tile in the group except the first and last one has a different color from its **adjacent** tiles in the group).

You have to process queries of two types:

*   queries[i] = [1, sizei], determine the count of **alternating** groups with size sizei.
*   queries[i] = [2, indexi, colori], change colors[indexi] to colori.

Return an array `answer` containing the results of the queries of the first type _in order_.

**Note** that since `colors` represents a **circle**, the **first** and the **last** tiles are considered to be next to each other.

**Example 1:**

**Input:** colors = [0,1,1,0,1], queries = [[2,1,0],[1,4]]

**Output:** [2]

**Explanation:**

**![](https://assets.leetcode.com/uploads/2024/06/03/screenshot-from-2024-06-03-20-14-44.png)**

First query:

Change `colors[1]` to 0.

![](https://assets.leetcode.com/uploads/2024/06/03/screenshot-from-2024-06-03-20-20-25.png)

Second query:

Count of the alternating groups with size 4:

![](https://assets.leetcode.com/uploads/2024/06/03/screenshot-from-2024-06-03-20-25-02-2.png)![](https://assets.leetcode.com/uploads/2024/06/03/screenshot-from-2024-06-03-20-24-12.png)

**Example 2:**

**Input:** colors = [0,0,1,0,1,1], queries = [[1,3],[2,3,0],[1,5]]

**Output:** [2,0]

**Explanation:**

![](https://assets.leetcode.com/uploads/2024/06/03/screenshot-from-2024-06-03-20-35-50.png)

First query:

Count of the alternating groups with size 3:

![](https://assets.leetcode.com/uploads/2024/06/03/screenshot-from-2024-06-03-20-37-13.png)![](https://assets.leetcode.com/uploads/2024/06/03/screenshot-from-2024-06-03-20-36-40.png)

Second query: `colors` will not change.

Third query: There is no alternating group with size 5.

**Constraints:**

*   4 <= colors.length <= 5 * 104
*   `0 <= colors[i] <= 1`
*   1 <= queries.length <= 5 * 104
*   `queries[i][0] == 1` or `queries[i][0] == 2`
*   For all `i` that:
    *   `queries[i][0] == 1`: `queries[i].length == 2`, `3 <= queries[i][1] <= colors.length - 1`
    *   `queries[i][0] == 2`: `queries[i].length == 3`, `0 <= queries[i][1] <= colors.length - 1`, `0 <= queries[i][2] <= 1`