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 theread4API, implement the functionint read(char *buf, int n)that readsncharacters from the file.

Note:
Thereadfunction will only be called once for each test case.

/* 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) {
        boolean eof = false;
        int total = 0;

        while (!eof && total < n){
            char[] tmp = new char[4];
            int count = read4(tmp);

            if (count < 4) eof = true;

            int actual = Math.min(count, n - total);
            for (int i = 0; i < actual; i++){
                buf[total++] = tmp[i];
            }
        }

        return total;
    }
}