refactor(structure): normalize folder names with leading zeros for consistency

- Renamed all folders from format NEx (e.g., 1Ex, 2Ex...) to 0NEx (01Ex, 02Ex, etc.)
- Updated subdirectories and files accordingly
- Removed old main Makefile and tasks (a01.c–a09.c, solve.c, io_status.h), likely obsolete
- Cleaned up deprecated task binaries and configs

2025.02.28/08Ex/solve.c

@@ -0,0 +1,43 @@
+#include "solve.h"
+
+void t8_solve(char **a, char **b, int n, int (*cmp)(const char *, const char *))
+{
+	int i = 2, j, margin;
+	do {
+		int hf_i = i/2;
+		for (j = 0; j < n; j += i)
+		{
+			if (n < j+i)
+			{
+				margin = n-(j+hf_i);
+				if (margin <= 0) break;
+			} else margin = hf_i;
+
+			unite(a+j, a+(j+hf_i), b, hf_i, margin, cmp);
+			for (int k = 0; k < hf_i+margin; k++) a[j+k] = b[k];
+		}
+
+		i *= 2;
+	} while (i < n*2);
+}
+
+void unite(char **arr_a, char **arr_b, char **arr_c, int n, int m, int (*cmp)(const char *, const char *))
+{
+ int i, j, k, cntr, len = n + m; // cntr - contrast
+ for (i = 0, j = 0, k = 0; k < len; ++k)
+ {
+  if (i >= n) 
+  {
+   arr_c[k] = arr_b[j++];
+  } else if (j >= m)
+  {
+   arr_c[k] = arr_a[i++];
+  } else 
+  {
+   cntr = cmp(arr_a[i], arr_b[j]);
+   if (cntr <= 0) arr_c[k] = arr_a[i++];
+   else arr_c[k] = arr_b[j++];
+  } 
+ }
+}
+