花园的最大总美丽值

/*
题目思路：
1. 对flowers数组排序，计算出使每个花园达到target所需的额外花数。
2. 使用滑动窗口或双指针的方法计算能够种满的花园数目，以及剩余不完善花园中的最小花数。
3. 计算并更新最大总美丽值。
*/
import java.util.*;
import java.util.stream.*;

public class Solution {
    public long maximumBeauty(int[] flowers, int newFlowers, int target, int full, int partial) {
        Arrays.sort(flowers);
        int n = flowers.length;
        long[] prefixSum = new long[n + 1];
        IntStream.range(1, n + 1).forEach(i -> prefixSum[i] = prefixSum[i - 1] + flowers[i - 1]);
        return IntStream.rangeClosed(0, n).mapToLong(i -> {
            if (i > 0 && flowers[i - 1] >= target) return 0;
            int remainingFlowers = newFlowers - (target * i - (prefixSum[n] - prefixSum[n - i]));
            if (remainingFlowers < 0) return 0;
            int left = 0, right = target - 1, minPartial = 0;
            while (left <= right) {
                int mid = (left + right) / 2;
                int pos = Arrays.binarySearch(flowers, 0, n - i, mid);
                if (pos < 0) pos = -pos - 1;
                long needed = (long) mid * pos - prefixSum[pos];
                if (needed <= remainingFlowers) {
                    minPartial = mid;
                    left = mid + 1;
                } else {
                    right = mid - 1;
                }
            }
            return (long) full * i + (long) partial * minPartial;
        }).max().orElse(0);
    }
}