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Java-based LeetCode algorithm problem solutions, regularly updated

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package g0901_1000.s0904_fruit_into_baskets;

// #Medium #Array #Hash_Table #Sliding_Window #2022_03_28_Time_6_ms_(95.60%)_Space_69.2_MB_(76.55%)

/**
 * 904 - Fruit Into Baskets\.
 *
 * Medium
 *
 * You are visiting a farm that has a single row of fruit trees arranged from left to right. The trees are represented by an integer array `fruits` where `fruits[i]` is the **type** of fruit the i^th tree produces.
 *
 * You want to collect as much fruit as possible. However, the owner has some strict rules that you must follow:
 *
 * *   You only have **two** baskets, and each basket can only hold a **single type** of fruit. There is no limit on the amount of fruit each basket can hold.
 * *   Starting from any tree of your choice, you must pick **exactly one fruit** from **every** tree (including the start tree) while moving to the right. The picked fruits must fit in one of your baskets.
 * *   Once you reach a tree with fruit that cannot fit in your baskets, you must stop.
 *
 * Given the integer array `fruits`, return _the **maximum** number of fruits you can pick_.
 *
 * **Example 1:**
 *
 * **Input:** fruits = [1,2,1]
 *
 * **Output:** 3
 *
 * **Explanation:** We can pick from all 3 trees.
 *
 * **Example 2:**
 *
 * **Input:** fruits = [0,1,2,2]
 *
 * **Output:** 3
 *
 * **Explanation:** We can pick from trees [1,2,2]. If we had started at the first tree, we would only pick from trees [0,1].
 *
 * **Example 3:**
 *
 * **Input:** fruits = [1,2,3,2,2]
 *
 * **Output:** 4
 *
 * **Explanation:** We can pick from trees [2,3,2,2]. If we had started at the first tree, we would only pick from trees [1,2].
 *
 * **Constraints:**
 *
 * *   1 <= fruits.length <= 10⁵
 * *   `0 <= fruits[i] < fruits.length`
**/
public class Solution {
    public int totalFruit(int[] fruits) {
        int end = 1;
        int basket1 = fruits[0];
        int basket2 = -1;
        int secondFruitIndex = -1;
        int maxTotal = 1;
        int counter = 1;
        while (end < fruits.length) {
            if (fruits[end - 1] != fruits[end]) {
                if (basket2 == -1) {
                    basket2 = fruits[end];
                    secondFruitIndex = end;
                    counter++;
                } else if (fruits[end] == basket1) {
                    basket1 = basket2;
                    basket2 = fruits[end];
                    secondFruitIndex = end;
                    counter++;
                } else {
                    counter = end - secondFruitIndex + 1;
                    basket1 = basket2;
                    basket2 = fruits[end];
                    secondFruitIndex = end;
                }
            } else {
                counter++;
            }
            end++;
            maxTotal = Math.max(maxTotal, counter);
        }
        return maxTotal;
    }
}