题解 | #做项目的最大收益问题#

import java.util.Comparator;
import java.util.PriorityQueue;
import java.util.Scanner;

public class Main {

    public static class Program {
        public int cost;
        public int profit;

        public Program(int cost, int profit) {
            this.cost = cost;
            this.profit = profit;
        }
    }

    //定义小根堆如何比较大小
    public static class costMinComp implements Comparator<Program> {
        @Override
        public int compare(Program o1, Program o2) {
            return o1.cost - o2.cost;
        }
    }

    //定义大根堆如何比较大小
    public static class costMaxComp implements Comparator<Program> {
        @Override
        public int compare(Program o1, Program o2) {
            return o2.profit - o1.profit;
        }
    }

    public static long getMaxMoney(long W, long K, int[] costs, int[] profits) {
        if (W < 1 || K < 0 || costs == null || profits == costs || costs.length != profits.length) {
            return W;
        }

        PriorityQueue<Program> costMinHeap = new PriorityQueue<>(new costMinComp());
        PriorityQueue<Program> profitMaxHeap = new PriorityQueue<>(new costMaxComp());
        for (int i = 0; i < costs.length; i++) {
            costMinHeap.add(new Program(costs[i], profits[i]));
        }

        //依次做K个项目
        for (int i = 1; i <=K ; i++) {
            while (!costMinHeap.isEmpty()&&costMinHeap.peek().cost<=W){
                profitMaxHeap.add(costMinHeap.poll());
            }
            if(profitMaxHeap.isEmpty()){
                return W;
            }
            W+=profitMaxHeap.poll().profit;
        }
        return W;
    }

    public static void main(String[] args) {
        Scanner in=new Scanner(System.in);
        String[] strings=in.nextLine().split(" ");
        int n=Integer.parseInt(strings[0]);
        int W=Integer.parseInt(strings[1]);
        int K=Integer.parseInt(strings[2]);
        int[] costs=new int[n];
        int[] profits=new int[n];
        for (int i = 0; i <n ; i++) {
            costs[i]=in.nextInt();
        }
        for (int i = 0; i <n ; i++) {
            profits[i]=in.nextInt();
        }
        long res=getMaxMoney(W,K,costs,profits);
        System.out.println(res);
    }
}