update: short code offset header

src/klotski_core/short_code/offset/all_cases_offset.h

@@ -1,12 +1,18 @@
 #pragma once
 
+/// This is the head index, the offset (0 ~ 29334498) in all cases is obtained
+/// according to the `head` (0 ~ 15). In other words, the short code range can be
+/// obtained according to the position of the 2x2 block.
+
 #include <cstdint>
 
 namespace klotski {
+
 const uint32_t ALL_CASES_OFFSET[16] = {
            0,  2942906,  5203298,  8146204,
      8146204, 10468254, 12345199, 14667249,
     14667249, 16989299, 18866244, 21188294,
     21188294, 24131200, 26391592, 29334498,
 };
-}
+
+} // namespace klotski

src/klotski_core/short_code/offset/basic_ranges_offset.h

@@ -1,8 +1,13 @@
 #pragma once
 
+/// This is the index for basic ranges, and its position (0 ~ 7311920) in all
+/// basic ranges is located according to the first 12-bit (0 ~ 4095) of the
+/// 32-bit `range`.
+
 #include <cstdint>
 
 namespace klotski {
+
 const uint32_t BASIC_RANGES_OFFSET[4096] = {
           0,   18272,   24960,   31648,   49920,   56608,   59056,   61504,
       68192,   74880,   77328,   79776,   86464,  104736,  111424,  118112,
@@ -517,4 +522,5 @@ namespace klotski {
     7189796, 7208068, 7214415, 7220762, 7238351, 7244698, 7246483, 7248268,
     7253514, 7259861, 7261646, 7263431, 7268677, 7286266, 7291512, 7296758,
 };
-}
+
+} // namespace klotski

src/klotski_core/short_code/offset/range_prefix_offset.h

@@ -1,8 +1,14 @@
 #pragma once
 
+/// This is the index for the range prefix. Given the `head` and the first
+/// 12-bit (0 ~ 4095) of the `range`, you can get the positions of all cases
+/// in the current `head`. That is, according to the position of 2x2 block
+/// and the `range`, the short code range is obtained.
+
 #include <cstdint>
 
 namespace klotski {
+
 const uint32_t RANGE_PREFIX_OFFSET[16][4096] = {{
 /// --------------------------------------------------------------------- 0x0 ---------------------------------------------------------------------
           0,    9527,   12991,   16067,   25594,   29058,   30527,   31657,   35121,   38525,   39766,   41041,   44445,   53972,   57436,   60512,
@@ -3108,4 +3114,5 @@ namespace klotski {
 }, {
 /// --------------------------------------------------------------------- 0xF ---------------------------------------------------------------------
 }};
-}
+
+} // namespace klotski