水题,提神专用!!!
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.StreamTokenizer;
/**
* 题意:输入 n 行,每行三个数。每列的数相加都等于零,就输出"YES",否则输出"NO"
*/
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 BufferedWriter(
new OutputStreamWriter(System.out)));
int lineNum; // 行数
int sumA;
int sumB;
int sumC;
while (in.nextToken() != StreamTokenizer.TT_EOF) {
lineNum = (int) in.nval;
sumA = 0;
sumB = 0;
sumC = 0;
while (lineNum-- != 0) {
in.nextToken();
sumA += in.nval;
in.nextToken();
sumB += in.nval;
in.nextToken();
sumC += in.nval;
}
out.println(sumA == 0 && sumB == 0 && sumC == 0 ? "YES" : "NO");
}
out.flush();
}
}