package q1461

func hasAllCodes(s string, k int) bool {
	if len(s) < (1<<k)+k-1 {
		return false
	}
	seen := make([]bool, 1<<k)
	nSeen := 0

	c := 0
	for i := range len(s) {
		c = (c << 1) + int(s[i]-'0')
		if i+1 >= k {
			if i >= k {
				c -= int(s[i-k]-'0') << k
			}

			if !seen[c] {
				seen[c] = true
				nSeen++
			}
		}
	}
	return nSeen == 1<<k
}

var _ = hasAllCodes