2309 added.

liuyubobobo · liuyubobobo · commit 03a9615a82d5 · 2022-06-21T11:22:55.000-07:00
diff --git a/2001-2500/2309-Greatest-English-Letter-in-Upper-and-Lower-Case/cpp-2309/CMakeLists.txt b/2001-2500/2309-Greatest-English-Letter-in-Upper-and-Lower-Case/cpp-2309/CMakeLists.txt
@@ -0,0 +1,6 @@
+cmake_minimum_required(VERSION 3.22)
+project(A)
+
+set(CMAKE_CXX_STANDARD 14)
+
+add_executable(A main.cpp)
diff --git a/2001-2500/2309-Greatest-English-Letter-in-Upper-and-Lower-Case/cpp-2309/main.cpp b/2001-2500/2309-Greatest-English-Letter-in-Upper-and-Lower-Case/cpp-2309/main.cpp
@@ -0,0 +1,35 @@
+/// Source : https://leetcode.com/problems/greatest-english-letter-in-upper-and-lower-case/
+/// Author : liuyubobobo
+/// Time   : 2022-06-21
+
+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+
+/// Simulation
+/// Time Complexity: O(n)
+/// Space Complexity: O(1)
+class Solution {
+public:
+    string greatestLetter(string s) {
+
+        vector<bool> upper(26, false), lower(26, false);
+        for(char c: s){
+            if(isupper(c)) upper[c - 'A'] = true;
+            else lower[c - 'a'] = true;
+        }
+
+        int res = -1;
+        for(int i = 0; i < 26; i ++)
+            if(upper[i] && lower[i]) res = i;
+        return res == -1 ? "" : string(1, 'A' + res);
+    }
+};
+
+
+int main() {
+
+    return 0;
+}
diff --git a/readme.md b/readme.md
@@ -2154,6 +2154,7 @@ email: [liuyubobobo@gmail.com](mailto:liuyubobobo@gmail.com)
 | 2306 | [Naming a Company](https://leetcode.com/problems/naming-a-company/) | [无] | [C++](2001-2500/2306-Naming-a-Company/cpp-2306/) | | |
 | | | | | | |
 | 2308 | Database Problem: [Link](https://github.com/liuyubobobo/Play-Leetcode-Database/) | - | - | - | - |
+| 2309 | [Greatest English Letter in Upper and Lower Case](https://leetcode.com/problems/greatest-english-letter-in-upper-and-lower-case/) | [无] | [C++](2001-2500/2309-Greatest-English-Letter-in-Upper-and-Lower-Case/cpp-2309/) | | |
 | | | | | | |
 | 2312 | [Selling Pieces of Wood](https://leetcode.com/problems/selling-pieces-of-wood/) | [无] | [C++](2001-2500/2312-Selling-Pieces-of-Wood/cpp-2312/) | | |
 | | | | | | |
