Added Generate Parentheses

Author: ignacio-chiazzo

GenerateParentheses.js

@@ -0,0 +1,54 @@
+/* 
+https://leetcode.com/problems/generate-parentheses
+
+Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.
+
+For example, given n = 3, a solution set is:
+
+[
+  "((()))",
+  "(()())",
+  "(())()",
+  "()(())",
+  "()()()"
+]
+*/
+
+var generateParentheses = function(n) {
+  if(n == 0) { return [""] };
+
+  var str = "(".repeat(n);
+  var sol = [];
+  genParAux(str, 0, 0, sol)
+  return sol;
+};
+
+var genParAux = function(str, position, leftParentheses, sol) {
+  if(position === str.length) {
+    var ret = str + ")".repeat(leftParentheses);
+    sol.push(ret);
+    return;
+  }
+
+  genParAux(str, position + 1, leftParentheses + 1, sol); // Don't insert anything
+  if(leftParentheses == 0) { return; }
+
+  for(var i = 1; i <= leftParentheses; i++) {
+    var parString = ")".repeat(i);
+    var partSol = str.slice(0, position) + parString + str.slice(position); // Insert i parentheses in the position
+    genParAux(partSol, position + i + 1, leftParentheses - i + 1, sol);
+  } 
+}
+
+function main() {
+  console.log("0:");
+  console.log(generateParentheses(0));
+  console.log("1:");
+  console.log(generateParentheses(1));
+  console.log("2:");
+  console.log(generateParentheses(2));
+  console.log("3:");
+  console.log(generateParentheses(3));
+}
+
+module.exports.main = main

Main.js

@@ -2,9 +2,11 @@
 var permutationWithoutDuplicates = require("./PermutationsWithoutDuplicates.js");
 var permutationWithDuplicates = require("./PermutationsWithDuplicates.js");
 var subsets = require("./Subsets.js");
+var generateParentheses = require("./GenerateParentheses.js")
 
 // Invocation
 
 // permutationWithoutDuplicates.main();
 // permutationWithDuplicates.main();
-// subsets.main();
+// subsets.main();
+// generateParentheses.main();