3474. Lexicographically Smallest Generated String

3474. Lexicographically Smallest Generated String/3474. Lexicographically Smallest Generated String.csproj

@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+    <RootNamespace>_3474._Lexicographically_Smallest_Generated_String</RootNamespace>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

3474. Lexicographically Smallest Generated String/Program.cs

@@ -0,0 +1,9 @@
+var sol = new Solution();
+
+// System.Console.WriteLine($"TFTF | ab -> \"{sol.GenerateString("TFTF", "ab")}\"");
+// System.Console.WriteLine($"TFTF | abc -> \"{sol.GenerateString("TFTF", "abc")}\"");
+// System.Console.WriteLine($"F | d -> \"{sol.GenerateString("F", "d")}\"");
+// System.Console.WriteLine($"F | da -> \"{sol.GenerateString("F", "da")}\"");
+// System.Console.WriteLine($"FT | da -> \"{sol.GenerateString("FT", "aghbdfhf")}\"");
+// System.Console.WriteLine($"TFFFTFFF | bab -> \"{sol.GenerateString("TFFFTFFF", "bab")}\"");
+System.Console.WriteLine($"TFT | xx -> \"{sol.GenerateString("TFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFTFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFTFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFT", "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa")}\"");

3474. Lexicographically Smallest Generated String/Solution.cs

@@ -0,0 +1,87 @@
+using System.Text;
+
+public class Solution
+{
+    public string GenerateString(string str1, string str2)
+    {
+        var len = str1.Length + str2.Length - 1;
+        var answer = new char[len];
+
+        // Сначала обработать все T
+        for (var i = 0; i < str1.Length; i++)
+        {
+            if (str1[i] == 'T')
+            {
+                var sbIdx = i;
+                for (var j = 0; j < str2.Length; j++)
+                {
+                    if (answer[sbIdx] != 0 && answer[sbIdx] != str2[j])
+                        return "";
+                    answer[sbIdx++] = str2[j];
+                }
+            }
+        }
+        // Теперь обработать все F
+        var canChange = new bool[len];
+        var lastF = -1;
+        for (var i = 0; i < str1.Length; i++)
+            if (str1[i] == 'F')
+            {
+                if (ProcessF(answer.AsSpan()[i..(i + str2.Length)], str2, canChange.AsSpan()[i..(i + str2.Length)], out var goBack) == false)
+                    return "";
+                if(goBack && lastF != -1) 
+                    i = lastF - 1;
+                else
+                    lastF = i;
+            }
+
+        return new string(answer);
+    }
+
+    private bool ProcessF(Span<char> chars, string s2, Span<bool> canChange, out bool goBack)
+    {
+        goBack = false;
+
+        var equal = true;
+        var emptyCount = 0;
+        var hasDiff = false;
+        var lastCanChange = -1;
+        for (var i = 0; i < s2.Length; i++)
+        {
+            equal &= chars[i] == s2[i];
+            if (chars[i] == 0)
+                emptyCount++;
+            else if (chars[i] != s2[i])
+                hasDiff = true;
+            if (canChange[i])
+                lastCanChange = i;
+        }
+        if (equal)
+        {
+            if (lastCanChange >= 0)
+            {
+                chars[lastCanChange]++;
+                if (chars[lastCanChange] == 'z' + 1)
+                    chars[lastCanChange] = 'a';
+                goBack = true;
+                return true;
+            }
+            else
+                return false;
+        }
+        for (var i = 0; i < chars.Length && emptyCount > 0; i++)
+        {
+            if (chars[i] != 0)
+                continue;
+            var insert = 'a';
+            if (emptyCount == 1 && s2[i] == insert && !hasDiff)
+                insert++;
+            chars[i] = insert;
+            canChange[i] = true;
+            if (s2[i] != insert)
+                hasDiff = true;
+            emptyCount--;
+        }
+        return true;
+    }
+}

Leetcode.sln

@@ -203,6 +203,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "2946. Matrix Similarity Aft
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "2840. Check if Strings Can be Made Equal With Operations II", "2840. Check if Strings Can be Made Equal With Operations II\2840. Check if Strings Can be Made Equal With Operations II.csproj", "{5020405E-5F4F-4AC6-932D-00F01643A2F0}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "3474. Lexicographically Smallest Generated String", "3474. Lexicographically Smallest Generated String\3474. Lexicographically Smallest Generated String.csproj", "{7493B586-527C-4D54-A048-2E9B96B52A6E}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -1413,6 +1415,18 @@ Global
 		{5020405E-5F4F-4AC6-932D-00F01643A2F0}.Release|x64.Build.0 = Release|Any CPU
 		{5020405E-5F4F-4AC6-932D-00F01643A2F0}.Release|x86.ActiveCfg = Release|Any CPU
 		{5020405E-5F4F-4AC6-932D-00F01643A2F0}.Release|x86.Build.0 = Release|Any CPU
+		{7493B586-527C-4D54-A048-2E9B96B52A6E}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{7493B586-527C-4D54-A048-2E9B96B52A6E}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{7493B586-527C-4D54-A048-2E9B96B52A6E}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{7493B586-527C-4D54-A048-2E9B96B52A6E}.Debug|x64.Build.0 = Debug|Any CPU
+		{7493B586-527C-4D54-A048-2E9B96B52A6E}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{7493B586-527C-4D54-A048-2E9B96B52A6E}.Debug|x86.Build.0 = Debug|Any CPU
+		{7493B586-527C-4D54-A048-2E9B96B52A6E}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{7493B586-527C-4D54-A048-2E9B96B52A6E}.Release|Any CPU.Build.0 = Release|Any CPU
+		{7493B586-527C-4D54-A048-2E9B96B52A6E}.Release|x64.ActiveCfg = Release|Any CPU
+		{7493B586-527C-4D54-A048-2E9B96B52A6E}.Release|x64.Build.0 = Release|Any CPU
+		{7493B586-527C-4D54-A048-2E9B96B52A6E}.Release|x86.ActiveCfg = Release|Any CPU
+		{7493B586-527C-4D54-A048-2E9B96B52A6E}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE