[nb] Commit

dynamic-programming/22-generate-parenthesis/golang/main.go

@@ -1,4 +1,8 @@
 package main
+import (
+  "strings"
+  "container/list"
+)
 /*
 Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.
 Example 1:
@@ -20,37 +24,30 @@ Constraints:
 1 <= n <= 8
 */
 
-func rec(int index, dp map[string]string) {
+func rec(input []string, left int, right int, n int, ans *[]string) {
+
+  if len(input) == 2*n {
+    *ans = append(*ans, strings.Join(input, ""))
+    return
+  }
+  if left < n {
+    input = append(input, "(")
+    rec(input, left+1, right, n, ans)
+    input = input[0:len(input)-1]
+  }
+  if right < left {
+    input = append(input, ")")
+    rec(input, left, right+1, n, ans)
+    input = input[0:len(input)-1]
+  }
 }
 
-
-func generateParenthesis(n int)[] string {
-
-  if n == 1 {
-    return []string{"()"}
-  }
-
-  if n == 2 {
-    return []string{"()()", "(())"}
-  }
-
-  var output = make([]string, 0) 
-  var dp = map[string]string{}
-  var start_string string = ""
-  for i := 0; i < n - 1; i++ {
-    start_string = start_string + "()"
-    out_arr = a
-  }
-  output = append(output, start_string)
-
-
-  for i := 1; i < n - 1; i++ {
-    result := rec(i+1, dp) + rec(i-1) 
-  }
-
-
+func generateParenthesis(n int) []string {
+  var output = make([]string, 2*n)
+  var input = make([]string, 2*n)
+  rec(input, 0, 0, n, &output)
+  return output
 }
-
 func main() {
-
+  generateParenthesis(3)
 }