题解 | 称砝码

import java.util.HashSet;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] weight = new int[n];
        int[] count = new int[n];
        for (int i = 0; i < n; i++) {
            weight[i] = sc.nextInt();
        }
        for (int i = 0; i < n; i++) {
            count[i] = sc.nextInt();
        }
        System.out.print(getMax(weight,count));
    }
    public static int getMax(int[] weight,int[] count){
        int len = weight.length;
        int maxWeight = 0;
        int result = 0;
        for (int i = 0; i < len; i++) {
            maxWeight = maxWeight + weight[i]*count[i];
        }
        int[] dp = new int[maxWeight + 1];
        dp[0] = 1;
        for (int i = 0; i < len; i++) {
            for (int j = maxWeight; j >= 0; j--) {
                if (dp[j] != 0){
                    for (int k = 0; k <= count[i]; k++) {
                        if (j + k*weight[i] <= maxWeight){
                            dp[j + k*weight[i]] = 1;
                        }
                    }
                }
            }
        }
        for (int i = 0; i <= maxWeight; i++) {
            if (dp[i] == 1){
                result++;
            }
        }
        return result;
    }
}