feat: 2025-10-30打卡

2025-10-30 16:31:25 +08:00
parent b897d019fa
commit 71664a10cc
3 changed files with 135 additions and 0 deletions
--- a/402.remove-k-digits.java
+++ b/402.remove-k-digits.java
@@ -0,0 +1,38 @@
+/*
+ * @lc app=leetcode id=402 lang=java
+ *
+ * [402] Remove K Digits
+ */
+
+// @lc code=start
+class Solution {
+    public String removeKdigits(String num, int k) {
+        ArrayDeque<Character> stack = new ArrayDeque<>();
+        for(int i = 0; i < num.length(); i++) {
+            if(k == 0) {
+                stack.addLast(num.charAt(i));
+            } else {
+                while(k>0 && !stack.isEmpty() && stack.peekLast() > num.charAt(i)) {
+                    k--;
+                    stack.removeLast();
+                }
+                stack.addLast(num.charAt(i));
+            }
+        }
+        while(!stack.isEmpty() && k > 0) {
+            k--;
+            stack.removeLast();
+        }
+        // 消除开头的0
+        while(!stack.isEmpty() && stack.getFirst()=='0') {
+            stack.removeFirst();
+        }
+        StringBuilder sb = new StringBuilder();   
+        for(Character c : stack) {
+            sb.append(c);
+        }
+        return sb.isEmpty()?"0":sb.toString();
+    }
+}
+// @lc code=end
+