Update README

leetcode/0301.Remove-Invalid-Parentheses/README.md

@@ -1,4 +1,4 @@
-# [301. Remove Invalid Parentheses](https://leetcode-cn.com/problems/remove-invalid-parentheses/)
+# [301. Remove Invalid Parentheses](https://leetcode.com/problems/remove-invalid-parentheses/)
 
 
 ## 题目
@@ -53,3 +53,79 @@ Return all the possible results. You may return the answer in any order.
     - 得分小于0
     - lmoves小于0
     - rmoves小于0
+
+## 代码
+
+```go
+
+package leetcode
+
+var (
+	res      []string
+	mp       map[string]int
+	n        int
+	length   int
+	maxScore int
+	str      string
+)
+
+func removeInvalidParentheses(s string) []string {
+	lmoves, rmoves, lcnt, rcnt := 0, 0, 0, 0
+	for _, v := range s {
+		if v == '(' {
+			lmoves++
+			lcnt++
+		} else if v == ')' {
+			if lmoves != 0 {
+				lmoves--
+			} else {
+				rmoves++
+			}
+			rcnt++
+		}
+	}
+	n = len(s)
+	length = n - lmoves - rmoves
+	res = []string{}
+	mp = make(map[string]int)
+	maxScore = min(lcnt, rcnt)
+	str = s
+	backtrace(0, "", lmoves, rmoves, 0)
+	return res
+}
+
+func backtrace(i int, cur string, lmoves int, rmoves int, score int) {
+	if lmoves < 0 || rmoves < 0 || score < 0 || score > maxScore {
+		return
+	}
+	if lmoves == 0 && rmoves == 0 {
+		if len(cur) == length {
+			if _, ok := mp[cur]; !ok {
+				res = append(res, cur)
+				mp[cur] = 1
+			}
+			return
+		}
+	}
+	if i == n {
+		return
+	}
+	if str[i] == '(' {
+		backtrace(i+1, cur+string('('), lmoves, rmoves, score+1)
+		backtrace(i+1, cur, lmoves-1, rmoves, score)
+	} else if str[i] == ')' {
+		backtrace(i+1, cur+string(')'), lmoves, rmoves, score-1)
+		backtrace(i+1, cur, lmoves, rmoves-1, score)
+	} else {
+		backtrace(i+1, cur+string(str[i]), lmoves, rmoves, score)
+	}
+}
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+```