题目：

题解：

const L = 10
var bin = map[byte]int{'A': 0, 'C': 1, 'G': 2, 'T': 3}func findRepeatedDnaSequences(s string) (ans []string) {n := len(s)if n <= L {return}x := 0for _, ch := range s[:L-1] {x = x<<2 | bin[byte(ch)]}cnt := map[int]int{}for i := 0; i <= n-L; i++ {x = (x<<2 | bin[s[i+L-1]]) & (1<<(L*2) - 1)cnt[x]++if cnt[x] == 2 {ans = append(ans, s[i:i+L])}}return ans
}