2025-05-17提交

22.generate-parentheses.java

@@ -0,0 +1,33 @@
+/*
+ * @lc app=leetcode id=22 lang=java
+ *
+ * [22] Generate Parentheses
+ */
+
+// @lc code=start
+class Solution {
+    public List<String> generateParenthesis(int n) {
+        List<String> r = new ArrayList<String>();
+        dfsGenParenthesis(r, "", 0, 0, n);
+        return r;
+    }
+
+    private void dfsGenParenthesis(List<String> r, String s, int i, int k, int n) {
+        if(i == n && k == 0) {
+            r.add(s);
+            return;
+        } else if(i > n) {
+            return;
+        }
+        if(i < n) {
+            String t = s + "(";
+            dfsGenParenthesis(r, t, i+1, k+1, n);
+        }
+        if(k > 0) {
+            String t = s + ")";
+            dfsGenParenthesis(r, t, i, k-1, n);
+        }
+    }
+}
+// @lc code=end
+