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Java-based LeetCode algorithm problem solutions, regularly updated

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package g1301_1400.s1388_pizza_with_3n_slices;

// #Hard #Array #Dynamic_Programming #Greedy #Heap_Priority_Queue
// #2022_03_17_Time_5_ms_(93.33%)_Space_42.4_MB_(88.57%)

/**
 * 1388 - Pizza With 3n Slices\.
 *
 * Hard
 *
 * There is a pizza with `3n` slices of varying size, you and your friends will take slices of pizza as follows:
 *
 * *   You will pick **any** pizza slice.
 * *   Your friend Alice will pick the next slice in the anti-clockwise direction of your pick.
 * *   Your friend Bob will pick the next slice in the clockwise direction of your pick.
 * *   Repeat until there are no more slices of pizzas.
 *
 * Given an integer array `slices` that represent the sizes of the pizza slices in a clockwise direction, return _the maximum possible sum of slice sizes that you can pick_.
 *
 * **Example 1:**
 *
 * ![](https://assets.leetcode.com/uploads/2020/02/18/sample_3_1723.png)
 *
 * **Input:** slices = [1,2,3,4,5,6]
 *
 * **Output:** 10
 *
 * **Explanation:** Pick pizza slice of size 4, Alice and Bob will pick slices with size 3 and 5 respectively. Then Pick slices with size 6, finally Alice and Bob will pick slice of size 2 and 1 respectively. Total = 4 + 6.
 *
 * **Example 2:**
 *
 * ![](https://assets.leetcode.com/uploads/2020/02/18/sample_4_1723.png)
 *
 * **Input:** slices = [8,9,8,6,1,1]
 *
 * **Output:** 16
 *
 * **Explanation:** Pick pizza slice of size 8 in each turn. If you pick slice with size 9 your partners will pick slices of size 8.
 *
 * **Constraints:**
 *
 * *   `3 * n == slices.length`
 * *   `1 <= slices.length <= 500`
 * *   `1 <= slices[i] <= 1000`
**/
public class Solution {
    public int maxSizeSlices(int[] slices) {
        int n = slices.length;
        int third = n / 3;
        return Math.max(
                maxSizeSlices(slices, 0, n - 2, third), maxSizeSlices(slices, 1, n - 1, third));
    }

    private int maxSizeSlices(int[] slices, int start, int end, int parts) {
        int[] dp = new int[slices.length];
        int res = 0;
        for (int i = 0; i < parts; i++) {
            int prev = 0;
            int prevPrev = 0;
            for (int j = end; j >= start; j--) {
                int curr = dp[j];
                dp[j] = slices[j] + prevPrev;
                prevPrev = prev;
                prev = Math.max(curr, prev);
                res = Math.max(res, dp[j]);
            }
        }
        return res;
    }
}