feat: add solutions to leetcode problem: No.1796. Second Largest Digit in a String

Author: yanglbme

solution/1700-1799/1796.Second Largest Digit in a String/README.md

@@ -37,27 +37,63 @@
 	<li><code>s</code> 只包含小写英文字母和（或）数字。</li>
 </ul>
 
-
 ## 解法
 
 <!-- 这里可写通用的实现逻辑 -->
 
+假设字符串最大的数为 `largestDigit`，第二大的数为 `secondLargestDigit`，初始化均为 -1。
+
+遍历字符串，判断当前字符是否为数字型字符。若是，先转为数字 `num`。然后判断数字与 `largestDigit`、`secondLargestDigit` 的大小关系：
+
+- 若 `num > largestDigit`，将 `secondLargestDigit` 更新为 `largestDigit`，而 `largestDigit` 更新为 num；
+- 若 `num > secondLargestDigit`，并且 `num < largestDigit`，将 `secondLargestDigit` 更新为 num；
+- 其他情况不做处理。
+
+最后返回 `secondLargestDigit` 即可。
+
 <!-- tabs:start -->
 
 ### **Python3**
 
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```python
-
+class Solution:
+    def secondHighest(self, s: str) -> int:
+        largest_digit = second_largest_digit = -1
+        for c in s:
+            if c.isdigit():
+                num = int(c)
+                if num > largest_digit:
+                    second_largest_digit, largest_digit = largest_digit, num
+                elif num > second_largest_digit and num < largest_digit:
+                    second_largest_digit = num
+        return second_largest_digit
 ```
 
 ### **Java**
 
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```java
-
+class Solution {
+    public int secondHighest(String s) {
+        int largestDigit = -1, secondLargestDigit = -1;
+        for (int i = 0; i < s.length(); ++i) {
+            char c = s.charAt(i);
+            if (c >= '0' && c <= '9') {
+                int num = c - '0';
+                if (num > largestDigit) {
+                    secondLargestDigit = largestDigit;
+                    largestDigit = num;
+                } else if (num > secondLargestDigit && num < largestDigit) {
+                    secondLargestDigit = num;
+                }
+            }
+        }
+        return secondLargestDigit;
+    }
+}
 ```
 
 ### **...**

solution/1700-1799/1796.Second Largest Digit in a String/README_EN.md

@@ -33,21 +33,47 @@
 	<li><code>s</code> consists of only lowercase English letters and/or digits.</li>
 </ul>
 
-
 ## Solutions
 
 <!-- tabs:start -->
 
 ### **Python3**
 
 ```python
-
+class Solution:
+    def secondHighest(self, s: str) -> int:
+        largest_digit = second_largest_digit = -1
+        for c in s:
+            if c.isdigit():
+                num = int(c)
+                if num > largest_digit:
+                    second_largest_digit, largest_digit = largest_digit, num
+                elif num > second_largest_digit and num < largest_digit:
+                    second_largest_digit = num
+        return second_largest_digit
 ```
 
 ### **Java**
 
 ```java
-
+class Solution {
+    public int secondHighest(String s) {
+        int largestDigit = -1, secondLargestDigit = -1;
+        for (int i = 0; i < s.length(); ++i) {
+            char c = s.charAt(i);
+            if (c >= '0' && c <= '9') {
+                int num = c - '0';
+                if (num > largestDigit) {
+                    secondLargestDigit = largestDigit;
+                    largestDigit = num;
+                } else if (num > secondLargestDigit && num < largestDigit) {
+                    secondLargestDigit = num;
+                }
+            }
+        }
+        return secondLargestDigit;
+    }
+}
 ```
 
 ### **...**

solution/1700-1799/1796.Second Largest Digit in a String/Solution.java

@@ -0,0 +1,18 @@
+class Solution {
+    public int secondHighest(String s) {
+        int largestDigit = -1, secondLargestDigit = -1;
+        for (int i = 0; i < s.length(); ++i) {
+            char c = s.charAt(i);
+            if (c >= '0' && c <= '9') {
+                int num = c - '0';
+                if (num > largestDigit) {
+                    secondLargestDigit = largestDigit;
+                    largestDigit = num;
+                } else if (num > secondLargestDigit && num < largestDigit) {
+                    secondLargestDigit = num;
+                }
+            }
+        }
+        return secondLargestDigit;
+    }
+}

solution/1700-1799/1796.Second Largest Digit in a String/Solution.py

@@ -0,0 +1,11 @@
+class Solution:
+    def secondHighest(self, s: str) -> int:
+        largest_digit = second_largest_digit = -1
+        for c in s:
+            if c.isdigit():
+                num = int(c)
+                if num > largest_digit:
+                    second_largest_digit, largest_digit = largest_digit, num
+                elif num > second_largest_digit and num < largest_digit:
+                    second_largest_digit = num
+        return second_largest_digit