Solution.go

/**
 * The read4 API is already defined for you.
 *
 *     read4 := func(buf4 []byte) int
 *
 * // Below is an example of how the read4 API can be called.
 * file := File("abcdefghijk") // File is "abcdefghijk", initially file pointer (fp) points to 'a'
 * buf4 := make([]byte, 4) // Create buffer with enough space to store characters
 * read4(buf4) // read4 returns 4. Now buf = ['a','b','c','d'], fp points to 'e'
 * read4(buf4) // read4 returns 4. Now buf = ['e','f','g','h'], fp points to 'i'
 * read4(buf4) // read4 returns 3. Now buf = ['i','j','k',...], fp points to end of file
 */

var solution = func(read4 func([]byte) int) func([]byte, int) int {
	// implement read below.
	return func(buf []byte, n int) int {
		buf4 := make([]byte, 4)
		i, v := 0, 5
		for v >= 4 {
			v = read4(buf4)
			for j := 0; j < v; j++ {
				buf[i] = buf4[j]
				i++
				if i >= n {
					return n
				}
			}
		}
		return i
	}
}