Read N Characters Given Read4

The API: int read4(char *buf) reads 4 characters at a time from a file.

The return value is the actual number of characters read. For example, it returns 3 if there is only 3 characters left in the file.

By using the read4 API, implement the function int read(char *buf, int n) that reads n characters from the file.

Note:
The read function will only be called once for each test case.

这题用C 写应该简单很多。

/* The read4 API is defined in the parent class Reader4.
      int read4(char[] buf); */

public class Solution extends Reader4 {
    /**
     * @param buf Destination buffer
     * @param n   Maximum number of characters to read
     * @return    The number of characters read
     */
    public int read(char[] buf, int n) {
        int result = 0;
        char[] tmp = new char[4];
        while(result < n){
            int size = super.read4(tmp);
            for(int i = 0; i < size && result < n; i ++, result ++){
                buf[result] = tmp[i];
            }
            if(size < 4) break;
        }
        return result;
    }
}