题目描述:
数字 n 代表生成括号的对数,请你设计一个函数,用于能够生成所有可能的并且 有效的 括号组合。
解析:
深度优先遍历
Java:
class Solution {
List<String> res = new ArrayList<>();
public List<String> generateParenthesis(int n) {
dfs(n, n, "");
return res;
}
private void dfs(int left, int right, String curStr) {
if(left == 0 && right == 0) {
res.add(curStr);
return;
}
if(left > 0) {
dfs(left - 1, right, curStr + "(");
}
if(right > left) {
dfs(left, right - 1, curStr + ")");
}
}
}
JavaScript:
var generateParenthesis = function(n) {
let res = [];
dfs(n, n, "");
return res;
function dfs(left, right, curStr) {
if(left === 0 && right === 0) {
res.push(curStr);
return;
}
if(left > 0) {
dfs(left - 1, right, curStr + "(");
}
if(right > left) {
dfs(left, right - 1, curStr + ")");
}
}
};