lintcode： 左填充

题目

实现一个leftpad库，如果不知道什么是leftpad可以看样例

样例

leftpad("foo", 5)
>> "  foo"

leftpad("foobar", 6)
>> "foobar"

leftpad("1", 2, "0")
>> "01"

解题
public class StringUtils {
    /**
     * @param originalStr the string we want to append to with spaces
     * @param size the target length of the string
     * @return a string
     */
    static public String leftPad(String originalStr, int size) {
        // Write your code here
        int n = originalStr.length();
        if(n>=size)
            return originalStr;
        int k = size - n;
        StringBuffer newStr = new StringBuffer();
        while(k>=1){
            newStr.append(' ');
            k--;
        }
        newStr.append(originalStr);
        return newStr.toString();
    }

    /**
     * @param originalStr the string we want to append to
     * @param size the target length of the string
     * @param padChar the character to pad to the left side of the string
     * @return a string
     */
    static public String leftPad(String originalStr, int size, char padChar) {
        // Write your code here
        int n = originalStr.length();
        if(n>=size)
            return originalStr;
        int k = size - n;
        StringBuffer newStr = new StringBuffer();
        while(k>=1){
            newStr.append(padChar);
            k--;
        }
        newStr.append(originalStr);
        return newStr.toString();
    }
}