2018 day5 part1

1 files changed, 75 insertions, 0 deletions

diff --git a/src/2018/day5/aoc.cpp b/src/2018/day5/aoc.cpp
index 585f144..5b6d3cb 100644
--- a/src/2018/day5/aoc.cpp
+++ b/src/2018/day5/aoc.cpp
@@ -1,5 +1,80 @@
 #include "aoc.h"
+#include <math.h>
 
 namespace aoc2018 {
 
+void deduct(char** pp1, char** pp2, char* b, char* e) {
+  char* p1 = *pp1;
+  char* p2 = *pp2;
+  while (p1 >= b && p2 < e) {
+    bool stop = true;
+    if (std::abs(*p1 - *p2) == 32) {
+      *p1 = ' ';
+      *p2 = ' ';
+      p1--;
+      p2++;
+      stop = false;
+    }
+    if (*p1 == ' ') {
+      p1--;
+      stop = false;
+    }
+    if (*p2 == ' ') {
+      p2++;
+      stop = false;
+    }
+    if (stop) {
+      break;
+    }
+  }
+  *pp1 = p1;
+  *pp2 = p2;
 }
+
+int count(line_view lv) {
+  int total{0};
+  auto is_az = [](char c) { return c >= 'a' && c <= 'z'; };
+  auto is_AZ = [](char c) { return c >= 'A' && c <= 'Z'; };
+  per_char(lv, [&total, &is_az, &is_AZ](char c) {
+    if (is_az(c) || is_AZ(c)) {
+      total += 1;
+    }
+    return true;
+  });
+  return total;
+}
+
+void deduct(char* p1, char* p2) {
+  char* p = p1;
+  while (p < p2) {
+    if (std::abs(*p - *(p + 1)) == 32) {
+      char* pa = p;
+      char* pb = p + 1;
+      deduct(&pa, &pb, p1, p2);
+      p = pb;
+    } else {
+      p++;
+    }
+  }
+}
+
+void print(char* p1, char* p2) {
+  while (p1 < p2) {
+    if (*p1 != ' ') {
+      std::cout << *p1;
+    }
+    p1++;
+  }
+  printf("\n");
+}
+
+int day5(line_view file) {
+  char* p1 = (char*)malloc(file.length);
+  memcpy(p1, file.line, file.length);
+  char* p2 = p1 + file.length;
+  deduct(p1, p2);
+  // print(p1, p2);
+  return count({p1, p2});
+}
+
+} // namespace aoc2018