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| 1 | +/* |
| 2 | +https://leetcode.com/problems/generate-parentheses |
| 3 | + |
| 4 | +Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. |
| 5 | + |
| 6 | +For example, given n = 3, a solution set is: |
| 7 | + |
| 8 | +[ |
| 9 | + "((()))", |
| 10 | + "(()())", |
| 11 | + "(())()", |
| 12 | + "()(())", |
| 13 | + "()()()" |
| 14 | +] |
| 15 | +*/ |
| 16 | + |
| 17 | +var generateParentheses = function(n) { |
| 18 | + if(n == 0) { return [""] }; |
| 19 | + |
| 20 | + var str = "(".repeat(n); |
| 21 | + var sol = []; |
| 22 | + genParAux(str, 0, 0, sol) |
| 23 | + return sol; |
| 24 | +}; |
| 25 | + |
| 26 | +var genParAux = function(str, position, leftParentheses, sol) { |
| 27 | + if(position === str.length) { |
| 28 | + var ret = str + ")".repeat(leftParentheses); |
| 29 | + sol.push(ret); |
| 30 | + return; |
| 31 | + } |
| 32 | + |
| 33 | + genParAux(str, position + 1, leftParentheses + 1, sol); // Don't insert anything |
| 34 | + if(leftParentheses == 0) { return; } |
| 35 | + |
| 36 | + for(var i = 1; i <= leftParentheses; i++) { |
| 37 | + var parString = ")".repeat(i); |
| 38 | + var partSol = str.slice(0, position) + parString + str.slice(position); // Insert i parentheses in the position |
| 39 | + genParAux(partSol, position + i + 1, leftParentheses - i + 1, sol); |
| 40 | + } |
| 41 | +} |
| 42 | + |
| 43 | +function main() { |
| 44 | + console.log("0:"); |
| 45 | + console.log(generateParentheses(0)); |
| 46 | + console.log("1:"); |
| 47 | + console.log(generateParentheses(1)); |
| 48 | + console.log("2:"); |
| 49 | + console.log(generateParentheses(2)); |
| 50 | + console.log("3:"); |
| 51 | + console.log(generateParentheses(3)); |
| 52 | +} |
| 53 | + |
| 54 | +module.exports.main = main |
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