题目：

题解：

func longestCommonPrefix(strs []string) string {
    if len(strs) == 0 {
        return ""
    }

    isCommonPrefix := func(length int) bool {
        str0, count := strs[0][:length], len(strs)
        for i := 1; i < count; i++ {
            if strs[i][:length] != str0 {
                return false
            }
        }
        return true
    }
    minLength := len(strs[0])
    for _, s := range strs {
        if len(s) < minLength {
            minLength = len(s)
        }
    }
    low, high := 0, minLength
    for low < high {
        mid := (high - low + 1) / 2 + low
        if isCommonPrefix(mid) {
            low = mid
        } else {
            high = mid - 1
        }
    }
    return strs[0][:low]
}