Problem Statement |
| |
A square matrix is a grid of NxN numbers. For example, the following is a 3x3 matrix: 4 3 5
2 4 5
0 1 9 One
way to represent a matrix of numbers, each of which is between 0 and 9
inclusive, is as a row-major String. To generate the String, simply
concatenate all of the elements from the first row followed by the
second row and so on, without any spaces. For example, the above matrix
would be represented as "435245019".
You will be given a square
matrix as a row-major String. Your task is to convert it into a
String[], where each element represents one row of the original matrix.
Element i of the String[] represents row i of the matrix. You should
not include any spaces in your return. Hence, for the above String, you
would return {"435","245","019"}. If the input does not represent a
square matrix because the number of characters is not a perfect square,
return an empty String[], {}. |
Definition |
| |
| Class: |
MatrixTool |
| Method: |
convert |
| Parameters: |
String |
| Returns: |
String[] |
| Method signature: |
String[] convert(String s) |
| (be sure your method is public) | |
public class MatrixTool
{
public String[] convert(String str)
{
String[] matrix = null;
if(str==null || str.length()<1)
{
return matrix;
}
int total = str.length();
double d = total/1.0;
int len = (int)Math.sqrt(d);
//check
for(int i=0;i<total;i++)
{
if(str.charAt(i)>='0' && str.charAt(i)<='9')
{
}
else
{
System.out.println("invaid charareter.");
return matrix;
}
}
if(len*len == total)
{
matrix = new String[len];
for(int i=0;i<len;i++)
{
matrix[i] = "";
for(int j=0;j<len;j++)
{
matrix[i]+= str.charAt(i*len+j);
}
}
}
return matrix;
}
public static void main(String args[]){
MatrixTool mt = new MatrixTool();
String[] temp = mt.convert("435245019");
for(int i=0;i<temp.length;i++){
System.out.println(temp[i]);
}
}
}
Feedback
# re: GOOGLE挑战赛练习题2及答案(500分) 回复
2005-11-29 15:01 by
public class MatrixTool {
public String[] convert(String s){
String[] error={};
if(s==null)return error;
StringBuffer buffer=new StringBuffer(s);
int length=s.length();
if(!(length>=1&&length<=50))
return error;
double f=Math.sqrt(length);
int n=(int)f;
if((n*n)!=length)
return error;
for(int i=0;i<length;i++){
if(!Character.isDigit(s.charAt(i)))
return error;
}
int count=0;
for (int i=n;i<length;i+=n){
buffer.insert(i+count,'#');
count++;
}
String [] s2=buffer.toString().split("#");
return s2;
}
}
问问为什么我写的只得了202。33分和时间有关系么？