签到题没啥好说的
直接每一组的乘积之和即为结果
import java.math.*; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.io.OutputStreamWriter; import java.io.PrintWriter; import java.io.StreamTokenizer; import java.util.*; public class Main { public static void main(String args[])throws IOException { StreamTokenizer in = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in))); PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out)); in.nextToken(); int T = (int)in.nval; while(T-->0) { in.nextToken(); int n = (int)in.nval; long ans=0; for(int i=0;i<n;i++) { in.nextToken(); int x = (int)in.nval; in.nextToken(); int y = (int)in.nval; ans+=x*y; } out.println(ans); out.flush(); } } }