Add <cassert> header include

This fixes some Linux build failures.

2015/puzzle-04-01.cc

@@ -15,7 +15,7 @@ auto md5(MD5Digest& digest, std::string const& s) -> unsigned int
 
   EVP_MD_CTX* md_context{EVP_MD_CTX_new()};
   assert(md_context != nullptr);
-  EVP_DigestInit_ex2(md_context, md, nullptr);
+  EVP_DigestInit_ex(md_context, md, nullptr);
   EVP_DigestUpdate(md_context, s.data(), s.length());
   EVP_DigestFinal_ex(md_context, digest.data(), &md_len);
   return md_len;

2015/puzzle-04-02.cc

@@ -15,7 +15,7 @@ auto md5(MD5Digest& digest, std::string const& s) -> unsigned int
 
   EVP_MD_CTX* md_context{EVP_MD_CTX_new()};
   assert(md_context != nullptr);
-  EVP_DigestInit_ex2(md_context, md, nullptr);
+  EVP_DigestInit_ex(md_context, md, nullptr);
   EVP_DigestUpdate(md_context, s.data(), s.length());
   EVP_DigestFinal_ex(md_context, digest.data(), &md_len);
   return md_len;

2015/puzzle-22-01.cc

@@ -1,4 +1,5 @@
 #include <algorithm>
+#include <cassert>
 #include <cstdlib>
 #include <iostream>
 #include <limits>

2015/puzzle-22-02.cc

@@ -1,4 +1,5 @@
 #include <algorithm>
+#include <cassert>
 #include <cstdlib>
 #include <iostream>
 #include <limits>

2015/puzzle-23-01.cc

@@ -1,4 +1,5 @@
 #include <algorithm>
+#include <cassert>
 #include <cstdlib>
 #include <iostream>
 #include <limits>

2015/puzzle-23-02.cc

@@ -1,4 +1,5 @@
 #include <algorithm>
+#include <cassert>
 #include <cstdlib>
 #include <iostream>
 #include <limits>

2015/puzzle-25-01.cc

@@ -1,3 +1,4 @@
+#include <cassert>
 #include <cstdint>
 #include <iostream>
 #include <string>

2016/puzzle-01-01.cc

@@ -2,6 +2,7 @@
 // Created by Matthew Gretton-Dann on 02/12/2021.
 //
 
+#include <cassert>
 #include <iostream>
 #include <string>
 

2016/puzzle-01-02.cc

@@ -2,6 +2,7 @@
 // Created by Matthew Gretton-Dann on 02/12/2021.
 //
 
+#include <cassert>
 #include <iostream>
 #include <set>
 #include <string>

2016/puzzle-03-01.cc

@@ -3,6 +3,7 @@
 //
 
 #include <array>
+#include <cassert>
 #include <cctype>
 #include <iostream>
 #include <string>

2016/puzzle-03-02.cc

@@ -3,6 +3,7 @@
 //
 
 #include <array>
+#include <cassert>
 #include <cctype>
 #include <iostream>
 #include <string>

2016/puzzle-04-01.cc

@@ -2,6 +2,7 @@
 // Created by Matthew Gretton-Dann on 03/12/2021.
 //
 
+#include <cassert>
 #include <iostream>
 #include <map>
 #include <set>

2016/puzzle-04-02.cc

@@ -2,6 +2,7 @@
 // Created by Matthew Gretton-Dann on 03/12/2021.
 //
 
+#include <cassert>
 #include <iostream>
 #include <map>
 #include <set>

2016/puzzle-08-01.cc

@@ -3,6 +3,7 @@
 //
 
 #include <array>
+#include <cassert>
 #include <iostream>
 #include <numeric>
 #include <string>

2016/puzzle-08-02.cc

@@ -3,6 +3,7 @@
 //
 
 #include <array>
+#include <cassert>
 #include <iostream>
 #include <numeric>
 #include <string>

2016/puzzle-09-01.cc

@@ -2,6 +2,7 @@
 // Created by Matthew Gretton-Dann on 05/12/2021.
 //
 
+#include <cassert>
 #include <iostream>
 #include <string>
 

2016/puzzle-09-02.cc

@@ -2,6 +2,7 @@
 // Created by Matthew Gretton-Dann on 05/12/2021.
 //
 
+#include <cassert>
 #include <iostream>
 #include <string>
 

2016/puzzle-10-01.cc

@@ -3,6 +3,7 @@
 //
 
 #include <algorithm>
+#include <cassert>
 #include <iostream>
 #include <regex>
 #include <string>

2016/puzzle-10-02.cc

@@ -3,6 +3,7 @@
 //
 
 #include <algorithm>
+#include <cassert>
 #include <iostream>
 #include <regex>
 #include <string>

2016/puzzle-14-01.cc

@@ -3,6 +3,7 @@
 //
 
 #include <array>
+#include <cassert>
 #include <iostream>
 #include <string>
 #include <string_view>

2016/puzzle-14-02.cc

@@ -3,6 +3,7 @@
 //
 
 #include <array>
+#include <cassert>
 #include <iostream>
 #include <string>
 #include <string_view>

2016/puzzle-17-01.cc

@@ -3,6 +3,7 @@
 //
 
 #include <array>
+#include <cassert>
 #include <iostream>
 #include <set>
 #include <string>

2016/puzzle-17-02.cc

@@ -3,6 +3,7 @@
 //
 
 #include <array>
+#include <cassert>
 #include <iostream>
 #include <set>
 #include <string>

2016/puzzle-20-02.cc

@@ -1,3 +1,4 @@
+#include <cassert>
 #include <iomanip>
 #include <iostream>
 #include <numeric>

2021/puzzle-04-01.cc

@@ -3,6 +3,7 @@
 //
 
 #include <array>
+#include <cassert>
 #include <iomanip>
 #include <iostream>
 #include <numeric>

2021/puzzle-04-02.cc

@@ -3,6 +3,7 @@
 //
 
 #include <array>
+#include <cassert>
 #include <iomanip>
 #include <iostream>
 #include <numeric>

2021/puzzle-05-02.cc

@@ -2,6 +2,7 @@
 // Created by Matthew Gretton-Dann on 05/12/2021.
 //
 
+#include <cassert>
 #include <iostream>
 #include <map>
 #include <numeric>

2021/puzzle-08-02.cc

@@ -3,6 +3,7 @@
 //
 
 #include <array>
+#include <cassert>
 #include <iostream>
 #include <string>
 #include <vector>