ccf 稀疏向量Java答案

 

这是一个偏萌新的做法

import java.util.HashMap;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner v = new Scanner(System.in);
        int n = v.nextInt(), a = v.nextInt(), b = v.nextInt();
        long num = 0;
        HashMap<Integer, Long> product = new HashMap<>();
        for (int i = 0; i < a; i++) {
            int key = v.nextInt();
            long value = v.nextLong();
            product.put(key, value);
        }
        for (int i = 0; i < b; i++) {
            int key = v.nextInt();
            long value = v.nextLong();
            if (product.containsKey(key)) {
                num += product.get(key) * value;
            }
        }
        System.out.print(num);
    }
}

相信大家都可以看懂这串代码