6. zigzag conversion

The string “PAYPALISHIRING” is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font for better legibility)

    P   A   H   N
    A P L S I I G
    Y   I   R

And then read line by line: “PAHNAPLSIIGYIR”

Write the code that will take a string and make this conversion given a number of rows:

    string convert(string text, int nRows);

convert(“PAYPALISHIRING”, 3) should return “PAHNAPLSIIGYIR”.

题目描述：

给出一个整数数组和一个整数target,找出数组中两数之和等于target的数的索引

Solution:

维护两个指针指向当前相加的数组元素位置索引，依次向后移动，直到和等于target，把结果索引保存在一个长度为2的数组中，返回

java:

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public class  {
    public String convert(String s, int numRows) {
      StringBuilder result=new StringBuilder();
      if(s==null||numRows==0){
          return result;
      }  
      if(numRows==1){
          return s;
      }
    for(int i=0;i<numRows;i++){
        int n=2*numRows-2;
        for(int j=i;j<s.length();j+=n){
           result.append(s.charAt(j);
            if(i!=0&&i!=(numRows-1)){
                int temp=j+n-2*i;
                if(temp<s.length())
                result=result+s.charAt(temp);
            }
        }
    }
    return result;
    }
}