Create 2981.cpp

Author: CollieIsCute

2981.cpp

@@ -0,0 +1,39 @@
+#include <algorithm>
+#include <string>
+#include <string_view>
+#include <unordered_map>
+
+class Solution {
+    bool validString(std::string_view s, int n) {
+        std::unordered_map<std::string_view, int> um;
+        for (size_t i = 0; i + n <= s.size(); ++i) {
+            auto temp_view = s.substr(i, n);
+            if (std::all_of(temp_view.begin(), temp_view.end(),
+                            [&](char c) { return c == temp_view.front(); })) {
+                um[temp_view]++;
+            }
+        }
+        for (const auto& p : um) {
+            if (p.second >= 3) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+public:
+    int maximumLength(std::string s) {
+        int left = 1, right = s.size();
+        int result = -1;
+        while (left <= right) {
+            int mid = left + (right - left) / 2;
+            if (validString(s, mid)) {
+                result = mid;
+                left = mid + 1;
+            } else {
+                right = mid - 1;
+            }
+        }
+        return result;
+    }
+};