202006-2 csp稀疏向量java

 

思路：1.一维数组60 2 二维数组 60 3 hashmap 60 4最后参考网上 发现是因为结果是long的原因

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.StringTokenizer;

class Reader {
    static StringTokenizer token =new StringTokenizer("");
    static BufferedReader reader   =new BufferedReader (new InputStreamReader(System.in)) ;
    static String nextLine() throws IOException {
        return reader.readLine() ;
    }
    static  String next() throws IOException {
        while(!token.hasMoreTokens()) {
            token =new StringTokenizer(reader.readLine()) ;
        }
        return token.nextToken() ;
    }

    static int nextInt() throws IOException {
        return Integer.parseInt(next()) ;
    }
    static double nextDouble() throws IOException {
        return Double.parseDouble(next()) ;
    }

}
public class XiShu {



    public static void main(String[] args) throws IOException {
        int n = Reader.nextInt();
        int a = Reader.nextInt();
        int b = Reader.nextInt();
        HashMap<Integer,Integer> map = new HashMap<>();



        for (int i = 0; i < a;i++){

               int key = Reader.nextInt();
               int value = Reader.nextInt();
               map.put(key,value);

        }
        long sum = 0L;

        for (int i = 0; i < b;i++){

            int key = Reader.nextInt();
            int value = Reader.nextInt();
            if(key!=0 && map.containsKey(key)) sum += map.get(key) * value;

        }

       System.out.println(sum);
    }
}

样例输入 

10 3 4
4 5
7 -3
10 1
1 10
4 20
5 30
7 40