Added tasks 3206-3213

Author: javadev

src/main/java/g3201_3300/s3206_alternating_groups_i/Solution.java

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+package g3201_3300.s3206_alternating_groups_i;
+
+// #Easy #Array #Sliding_Window #2024_07_09_Time_1_ms_(97.24%)_Space_42.8_MB_(90.31%)
+
+public class Solution {
+    public int numberOfAlternatingGroups(int[] colors) {
+        int n = colors.length;
+        int count = 0;
+        if (colors[n - 1] != colors[0] && colors[0] != colors[1]) {
+            count++;
+        }
+        if (colors[n - 1] != colors[0] && colors[n - 1] != colors[n - 2]) {
+            count++;
+        }
+        for (int i = 1; i < n - 1; i++) {
+            if (colors[i] != colors[i - 1] && colors[i] != colors[i + 1]) {
+                count++;
+            }
+        }
+        return count;
+    }
+}

src/main/java/g3201_3300/s3206_alternating_groups_i/readme.md

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+3206\. Alternating Groups I
+
+Easy
+
+There is a circle of red and blue tiles. You are given an array of integers `colors`. 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**.
+
+Every 3 contiguous tiles in the circle with **alternating** colors (the middle tile has a different color from its **left** and **right** tiles) is called an **alternating** group.
+
+Return the number of **alternating** groups.
+
+**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 = [1,1,1]
+
+**Output:** 0
+
+**Explanation:**
+
+![](https://assets.leetcode.com/uploads/2024/05/16/image_2024-05-16_23-53-171.png)
+
+**Example 2:**
+
+**Input:** colors = [0,1,0,0,1]
+
+**Output:** 3
+
+**Explanation:**
+
+![](https://assets.leetcode.com/uploads/2024/05/16/image_2024-05-16_23-47-491.png)
+
+Alternating groups:
+
+**![](https://assets.leetcode.com/uploads/2024/05/16/image_2024-05-16_23-50-441.png)**![](https://assets.leetcode.com/uploads/2024/05/16/image_2024-05-16_23-48-211.png)**![](https://assets.leetcode.com/uploads/2024/05/16/image_2024-05-16_23-49-351.png)**
+
+**Constraints:**
+
+*   `3 <= colors.length <= 100`
+*   `0 <= colors[i] <= 1`

src/main/java/g3201_3300/s3207_maximum_points_after_enemy_battles/Solution.java

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+package g3201_3300.s3207_maximum_points_after_enemy_battles;
+
+// #Medium #Array #Greedy #2024_07_09_Time_1_ms_(100.00%)_Space_55.5_MB_(99.34%)
+
+public class Solution {
+    public long maximumPoints(int[] enemyEnergies, int currentEnergy) {
+        int n = enemyEnergies.length;
+        int min = enemyEnergies[0];
+        for (int i = 1; i < n; i++) {
+            min = Math.min(min, enemyEnergies[i]);
+        }
+        if (currentEnergy == 0 || currentEnergy < min) {
+            return 0;
+        }
+        long sum = currentEnergy;
+        for (int i = n - 1; i >= 0; i--) {
+            sum += enemyEnergies[i];
+        }
+        sum -= min;
+        return sum / min;
+    }
+}

src/main/java/g3201_3300/s3207_maximum_points_after_enemy_battles/readme.md

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+3207\. Maximum Points After Enemy Battles
+
+Medium
+
+You are given an integer array `enemyEnergies` denoting the energy values of various enemies.
+
+You are also given an integer `currentEnergy` denoting the amount of energy you have initially.
+
+You start with 0 points, and all the enemies are unmarked initially.
+
+You can perform **either** of the following operations **zero** or multiple times to gain points:
+
+*   Choose an **unmarked** enemy, `i`, such that `currentEnergy >= enemyEnergies[i]`. By choosing this option:
+    *   You gain 1 point.
+    *   Your energy is reduced by the enemy's energy, i.e. `currentEnergy = currentEnergy - enemyEnergies[i]`.
+*   If you have **at least** 1 point, you can choose an **unmarked** enemy, `i`. By choosing this option:
+    *   Your energy increases by the enemy's energy, i.e. `currentEnergy = currentEnergy + enemyEnergies[i]`.
+    *   The enemy `i` is **marked**.
+
+Return an integer denoting the **maximum** points you can get in the end by optimally performing operations.
+
+**Example 1:**
+
+**Input:** enemyEnergies = [3,2,2], currentEnergy = 2
+
+**Output:** 3
+
+**Explanation:**
+
+The following operations can be performed to get 3 points, which is the maximum:
+
+*   First operation on enemy 1: `points` increases by 1, and `currentEnergy` decreases by 2. So, `points = 1`, and `currentEnergy = 0`.
+*   Second operation on enemy 0: `currentEnergy` increases by 3, and enemy 0 is marked. So, `points = 1`, `currentEnergy = 3`, and marked enemies = `[0]`.
+*   First operation on enemy 2: `points` increases by 1, and `currentEnergy` decreases by 2. So, `points = 2`, `currentEnergy = 1`, and marked enemies = `[0]`.
+*   Second operation on enemy 2: `currentEnergy` increases by 2, and enemy 2 is marked. So, `points = 2`, `currentEnergy = 3`, and marked enemies = `[0, 2]`.
+*   First operation on enemy 1: `points` increases by 1, and `currentEnergy` decreases by 2. So, `points = 3`, `currentEnergy = 1`, and marked enemies = `[0, 2]`.
+
+**Example 2:**
+
+**Input:** enemyEnergies = [2], currentEnergy = 10
+
+**Output:** 5
+
+**Explanation:**
+
+Performing the first operation 5 times on enemy 0 results in the maximum number of points.
+
+**Constraints:**
+
+*   <code>1 <= enemyEnergies.length <= 10<sup>5</sup></code>
+*   <code>1 <= enemyEnergies[i] <= 10<sup>9</sup></code>
+*   <code>0 <= currentEnergy <= 10<sup>9</sup></code>

src/main/java/g3201_3300/s3208_alternating_groups_ii/Solution.java

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+package g3201_3300.s3208_alternating_groups_ii;
+
+// #Medium #Array #Sliding_Window #2024_07_09_Time_2_ms_(99.02%)_Space_63.3_MB_(22.96%)
+
+public class Solution {
+    public int numberOfAlternatingGroups(int[] colors, int k) {
+        int i = 0;
+        int len = 0;
+        int total = 0;
+        while (i < colors.length - 1) {
+            int j = i + 1;
+            if (colors[j] != colors[i]) {
+                len = 2;
+                j++;
+                while (j < colors.length && colors[j] != colors[j - 1]) {
+                    j++;
+                    len++;
+                }
+                if (j == colors.length) {
+                    break;
+                }
+                total += Math.max(0, (len - k + 1));
+            }
+            i = j;
+            len = 0;
+        }
+        if (colors[0] != colors[colors.length - 1]) {
+            // if(len == colors.length) {
+            //     return Math.max(0, colors.length);
+            // }
+            len = len == 0 ? 2 : len + 1;
+            int j = 1;
+            while (j < colors.length && colors[j] != colors[j - 1]) {
+                j++;
+                len++;
+            }
+            if (j >= k) {
+                len -= (j - k + 1);
+            }
+        }
+        total += Math.max(0, (len - k + 1));
+        return total;
+    }
+}

src/main/java/g3201_3300/s3208_alternating_groups_ii/readme.md

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+3208\. Alternating Groups II
+
+Medium
+
+There is a circle of red and blue tiles. You are given an array of integers `colors` and an integer `k`. 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 every `k` contiguous tiles in the circle with **alternating** colors (each tile in the group except the first and last one has a different color from its **left** and **right** tiles).
+
+Return the number of **alternating** groups.
+
+**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 = [0,1,0,1,0], k = 3
+
+**Output:** 3
+
+**Explanation:**
+
+**![](https://assets.leetcode.com/uploads/2024/06/19/screenshot-2024-05-28-183519.png)**
+
+Alternating groups:
+
+![](https://assets.leetcode.com/uploads/2024/05/28/screenshot-2024-05-28-182448.png)![](https://assets.leetcode.com/uploads/2024/05/28/screenshot-2024-05-28-182844.png)![](https://assets.leetcode.com/uploads/2024/05/28/screenshot-2024-05-28-183057.png)
+
+**Example 2:**
+
+**Input:** colors = [0,1,0,0,1,0,1], k = 6
+
+**Output:** 2
+
+**Explanation:**
+
+**![](https://assets.leetcode.com/uploads/2024/06/19/screenshot-2024-05-28-183907.png)**
+
+Alternating groups:
+
+![](https://assets.leetcode.com/uploads/2024/06/19/screenshot-2024-05-28-184128.png)![](https://assets.leetcode.com/uploads/2024/06/19/screenshot-2024-05-28-184240.png)
+
+**Example 3:**
+
+**Input:** colors = [1,1,0,1], k = 4
+
+**Output:** 0
+
+**Explanation:**
+
+![](https://assets.leetcode.com/uploads/2024/06/19/screenshot-2024-05-28-184516.png)
+
+**Constraints:**
+
+*   <code>3 <= colors.length <= 10<sup>5</sup></code>
+*   `0 <= colors[i] <= 1`
+*   `3 <= k <= colors.length`

src/main/java/g3201_3300/s3209_number_of_subarrays_with_and_value_of_k/Solution.java

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+package g3201_3300.s3209_number_of_subarrays_with_and_value_of_k;
+
+// #Hard #Array #Binary_Search #Bit_Manipulation #Segment_Tree
+// #2024_07_09_Time_7_ms_(100.00%)_Space_62.9_MB_(11.74%)
+
+public class Solution {
+    public long countSubarrays(int[] nums, int k) {
+        long ans = 0;
+        int left = 0;
+        int right = 0;
+        for (int i = 0; i < nums.length; i++) {
+            int x = nums[i];
+            for (int j = i - 1; j >= 0 && (nums[j] & x) != nums[j]; j--) {
+                nums[j] &= x;
+            }
+            while (left <= i && nums[left] < k) {
+                left++;
+            }
+            while (right <= i && nums[right] <= k) {
+                right++;
+            }
+            ans += right - left;
+        }
+        return ans;
+    }
+}

src/main/java/g3201_3300/s3209_number_of_subarrays_with_and_value_of_k/readme.md

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+3209\. Number of Subarrays With AND Value of K
+
+Hard
+
+Given an array of integers `nums` and an integer `k`, return the number of subarrays of `nums` where the bitwise `AND` of the elements of the subarray equals `k`.
+
+**Example 1:**
+
+**Input:** nums = [1,1,1], k = 1
+
+**Output:** 6
+
+**Explanation:**
+
+All subarrays contain only 1's.
+
+**Example 2:**
+
+**Input:** nums = [1,1,2], k = 1
+
+**Output:** 3
+
+**Explanation:**
+
+Subarrays having an `AND` value of 1 are: <code>[<ins>**1**</ins>,1,2]</code>, <code>[1,<ins>**1**</ins>,2]</code>, <code>[<ins>**1,1**</ins>,2]</code>.
+
+**Example 3:**
+
+**Input:** nums = [1,2,3], k = 2
+
+**Output:** 2
+
+**Explanation:**
+
+Subarrays having an `AND` value of 2 are: <code>[1,**<ins>2</ins>**,3]</code>, <code>[1,<ins>**2,3**</ins>]</code>.
+
+**Constraints:**
+
+*   <code>1 <= nums.length <= 10<sup>5</sup></code>
+*   <code>0 <= nums[i], k <= 10<sup>9</sup></code>

src/main/java/g3201_3300/s3210_find_the_encrypted_string/Solution.java

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+package g3201_3300.s3210_find_the_encrypted_string;
+
+// #Easy #String #2024_07_09_Time_1_ms_(100.00%)_Space_42.8_MB_(34.96%)
+
+public class Solution {
+    public String getEncryptedString(String s, int k) {
+        int n = s.length();
+        k = k % n;
+        StringBuilder str = new StringBuilder(s.substring(k, n));
+        str.append(s.substring(0, k));
+        return str.toString();
+    }
+}

src/main/java/g3201_3300/s3210_find_the_encrypted_string/readme.md

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+3210\. Find the Encrypted String
+
+Easy
+
+You are given a string `s` and an integer `k`. Encrypt the string using the following algorithm:
+
+*   For each character `c` in `s`, replace `c` with the <code>k<sup>th</sup></code> character after `c` in the string (in a cyclic manner).
+
+Return the _encrypted string_.
+
+**Example 1:**
+
+**Input:** s = "dart", k = 3
+
+**Output:** "tdar"
+
+**Explanation:**
+
+*   For `i = 0`, the 3<sup>rd</sup> character after `'d'` is `'t'`.
+*   For `i = 1`, the 3<sup>rd</sup> character after `'a'` is `'d'`.
+*   For `i = 2`, the 3<sup>rd</sup> character after `'r'` is `'a'`.
+*   For `i = 3`, the 3<sup>rd</sup> character after `'t'` is `'r'`.
+
+**Example 2:**
+
+**Input:** s = "aaa", k = 1
+
+**Output:** "aaa"
+
+**Explanation:**
+
+As all the characters are the same, the encrypted string will also be the same.
+
+**Constraints:**
+
+*   `1 <= s.length <= 100`
+*   <code>1 <= k <= 10<sup>4</sup></code>
+*   `s` consists only of lowercase English letters.