Go java 算法之括号生成示例详解

class Solution {
    public List<String> generateParenthesis(int n) {
        List<String> ans = new ArrayList<String>();
        backtrack(ans, new StringBuilder(), 0, 0, n);
        return ans;
    }
    public void backtrack(List<String> ans, StringBuilder cur, int open, int close, int max) {
        if (cur.length() == max * 2) {
            ans.add(cur.toString());
            return;
        }
        if (open < max) {
            cur.append('(');
            backtrack(ans, cur, open + 1, close, max);
            cur.deleteCharAt(cur.length() - 1);
        }
        if (close < open) {
            cur.append(')');
            backtrack(ans, cur, open, close + 1, max);
            cur.deleteCharAt(cur.length() - 1);
        }
    }
}

	var ans []string
	var backtrack func([]byte, int, int)
	backtrack = func(bytes []byte, left int, right int) {
		if len(bytes) == 2*n {
			ans = append(ans, string(bytes))
			return
		}
		if left < n {
			bytes = append(bytes,'(')
			backtrack(bytes, left+1, right)
			bytes = bytes[:len(bytes)-1]
		}
		if right < left{
			bytes = append(bytes, ')')
			backtrack(bytes, left, right + 1)
			bytes = bytes[:len(bytes)-1]
		}
	}
	var container []byte
	backtrack(container, 0, 0)
	return ans