Move all Advent of Codes into one repo

1 files changed, 127 insertions, 0 deletions

diff --git a/2020/01/part2_fast.c b/2020/01/part2_fast.c
new file mode 100644
index 0000000..c32f881
--- /dev/null
+++ b/2020/01/part2_fast.c
@@ -0,0 +1,127 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <immintrin.h>
+
+#define INPUT_LEN 200
+#define SEARCH 2020
+
+#ifdef USE_ASM
+int repair_avx_inner(const int *arr, __m256i search);
+#else
+int repair_avx_inner(const int *arr, __m256i search)
+{
+    for (int k = 0; k < INPUT_LEN; k += 8) {
+        __m256i new = _mm256_loadu_si256((__m256i *)(&arr[k]));
+        if (_mm256_movemask_epi8(_mm256_cmpeq_epi32(new, search))) {
+            return _mm256_extract_epi32(search, 0);
+        }
+    }
+
+    return 0;
+}
+#endif
+
+int repair_avx(const int *arr)
+{
+    __m256i search = _mm256_set1_epi32(SEARCH);
+    for (int i = 0; i < INPUT_LEN; i++) {
+        __m256i start = _mm256_set1_epi32(arr[i]);
+        for (int j = 0; j < INPUT_LEN; j += 8) {
+            __m256i new = _mm256_loadu_si256((__m256i *)(&arr[j]));
+            new = _mm256_add_epi32(start, new);
+            unsigned int mask = (unsigned int)_mm256_movemask_epi8(_mm256_cmpgt_epi32(new, search));
+            if (mask == 0xffffffff) {
+                continue;
+            }
+
+            switch (__lzcnt32(mask) / 4) {
+                case 0:
+                    {
+                        __m256i cmp = _mm256_sub_epi32(search, _mm256_permutevar8x32_epi32(new, _mm256_set1_epi32(7)));
+                        int tmp = repair_avx_inner(arr, cmp);
+                        if (tmp) {
+                            return tmp * arr[i] * arr[j + 7];
+                        }
+                    }
+                case 1:
+                    if ((mask & 0x0f000000) == 0) {
+                        __m256i cmp = _mm256_sub_epi32(search, _mm256_permutevar8x32_epi32(new, _mm256_set1_epi32(6)));
+                        int tmp = repair_avx_inner(arr, cmp);
+                        if (tmp) {
+                            return tmp * arr[i] * arr[j + 6];
+                        }
+                    }
+                case 2:
+                    if ((mask & 0x00f00000) == 0 ){
+                        __m256i cmp = _mm256_sub_epi32(search, _mm256_permutevar8x32_epi32(new, _mm256_set1_epi32(5)));
+                        int tmp = repair_avx_inner(arr, cmp);
+                        if (tmp) {
+                            return tmp * arr[i] * arr[j + 5];
+                        }
+                    }
+                case 3:
+                    if ((mask & 0x000f0000) == 0) {
+                        __m256i cmp = _mm256_sub_epi32(search, _mm256_permutevar8x32_epi32(new, _mm256_set1_epi32(4)));
+                        int tmp = repair_avx_inner(arr, cmp);
+                        if (tmp) {
+                            return tmp * arr[i] * arr[j + 4];
+                        }
+                    }
+                case 4:
+                    if ((mask & 0x0000f000) == 0) {
+                        __m256i cmp = _mm256_sub_epi32(search, _mm256_permutevar8x32_epi32(new, _mm256_set1_epi32(3)));
+                        int tmp = repair_avx_inner(arr, cmp);
+                        if (tmp) {
+                            return tmp * arr[i] * arr[j + 3];
+                        }
+                    }
+                case 5:
+                    if ((mask & 0x00000f00) == 0) {
+                        __m256i cmp = _mm256_sub_epi32(search, _mm256_permutevar8x32_epi32(new, _mm256_set1_epi32(2)));
+                        int tmp = repair_avx_inner(arr, cmp);
+                        if (tmp) {
+                            return tmp * arr[i] * arr[j + 2];
+                        }
+                    }
+                case 6:
+                    if ((mask & 0x000000f0) == 0) {
+                        __m256i cmp = _mm256_sub_epi32(search, _mm256_permutevar8x32_epi32(new, _mm256_set1_epi32(1)));
+                        int tmp = repair_avx_inner(arr, cmp);
+                        if (tmp) {
+                            return tmp * arr[i] * arr[j + 1];
+                        }
+                    }
+                case 7:
+                    if ((mask & 0x0000000f) == 0) {
+                        __m256i cmp = _mm256_sub_epi32(search, _mm256_permutevar8x32_epi32(new, _mm256_setzero_si256()));
+                        int tmp = repair_avx_inner(arr, cmp);
+                        if (tmp) {
+                            return tmp * arr[i] * arr[j];
+                        }
+                    }
+            }
+        }
+    }
+
+    return 0;
+}
+
+int main(int argc, char *argv[])
+{
+    FILE *file = fopen(argv[argc - 1], "r");
+    if (!file) {
+        return 1;
+    }
+
+    char buffer[8] = { 0 };
+    int input[INPUT_LEN] = { 0 };
+    for (int i = 0; i < 200; i++) {
+        fgets(buffer, 8, file);
+        input[i] = atoi(buffer);
+    }
+
+    fclose(file);
+
+    printf("%i\n", repair_avx(input));
+}