最小化舍入误差以满足目标

/*
题目思路:
1. 首先计算所有价格的向下舍入总和。
2. 使用Java Stream处理浮点数的差值集合。
3. 使用PriorityQueue来管理这些差值集合，并根据目标数量调整误差值。
*/

import java.util.*;
import java.util.stream.*;

public class MinimizeRoundingErrorStream {
    public String minimizeError(String[] prices, int target) {
        int floorSum = IntStream.range(0, prices.length)
                .map(i -> (int) Math.floor(Double.parseDouble(prices[i])))
                .sum();
        PriorityQueue<Double> pq = new PriorityQueue<>();
        double totalDiff = IntStream.range(0, prices.length)
                .mapToDouble(i -> {
                    double num = Double.parseDouble(prices[i]);
                    double diff = num - Math.floor(num);
                    if (diff > 0) pq.add(diff);
                    return diff;
                })
                .sum();
        int needCeil = target - floorSum;
        if (needCeil < 0 || needCeil > pq.size()) {
            return "-1";
        }
        double error = 0;
        for (int i = 0; i < needCeil; i++) {
            error += pq.poll();
        }
        error += pq.stream().mapToDouble(d -> 1 - d).sum();
        return String.format("%.3f", error);
    }
}