Golang | Leetcode Golang题解之第301题删除无效的括号
题目：
题解：
func checkValid(str string, lmask, rmask int, left, right []int) bool {cnt := 0pos1, pos2 := 0, 0for i := range str {if pos1 < len(left) && i == left[pos1] {if lmask>>pos1&1 == 0 {cnt++}pos1++} else if pos2 < len(right) && i == right[pos2] {if rmask>>pos2&1 == 0 {cnt--if cnt < 0 {return false}}pos2++}}return cnt == 0
}func recoverStr(str string, lmask, rmask int, left, right []int) string {res := []rune{}pos1, pos2 := 0, 0for i, ch := range str {if pos1 < len(left) && i == left[pos1] {if lmask>>pos1&1 == 0 {res = append(res, ch)}pos1++} else if pos2 < len(right) && i == right[pos2] {if rmask>>pos2&1 == 0 {res = append(res, ch)}pos2++} else {res = append(res, ch)}}return string(res)
}func removeInvalidParentheses(s string) (ans []string) {var left, right []intlremove, rremove := 0, 0for i, ch := range s {if ch == '(' {left = append(left, i)lremove++} else if ch == ')' {right = append(right, i)if lremove == 0 {rremove++} else {lremove--}}}var maskArr1, maskArr2 []intfor i := 0; i < 1<<len(left); i++ {if bits.OnesCount(uint(i)) == lremove {maskArr1 = append(maskArr1, i)}}for i := 0; i < 1<<len(right); i++ {if bits.OnesCount(uint(i)) == rremove {maskArr2 = append(maskArr2, i)}}res := map[string]struct{}{}for _, mask1 := range maskArr1 {for _, mask2 := range maskArr2 {if checkValid(s, mask1, mask2, left, right) {res[recoverStr(s, mask1, mask2, left, right)] = struct{}{}}}}for str := range res {ans = append(ans, str)}return
}