1 files changed, 44 insertions, 0 deletions
diff --git a/src/2022/day4/aoc.h b/src/2022/day4/aoc.h
index 3b8a1ec..b291262 100644
--- a/src/2022/day4/aoc.h
+++ b/src/2022/day4/aoc.h
@@ -3,6 +3,50 @@
 
 namespace aoc2022 {
 
+struct apair {
+  int first[2] = {0};
+  int second[2] = {0};
+
+  void get_number(int* d, int i, const char* p) {
+    *(d + i) = *(d + i) * 10 + *p - '0';
+  }
+
+  void load(line_view lv) {
+    int* d = first;
+    int i{0};
+    const char* p0 = lv.line;
+    while (p0 < lv.line + lv.length) {
+      if (*p0 >= '0' && *p0 <= '9') {
+        get_number(d, i, p0);
+      }
+      else {
+        if (*p0 == ',') {
+          d = second;
+          i = 0;
+        }
+        if (*p0 == '-') {
+          i += 1;
+        }
+      }
+      p0++;
+    }
+  }
+
+  bool covered() const noexcept {
+    bool b1 = first[0] <= second[0] && first[1]  >= second[1];
+    bool b2 = second[0] <= first[0] && second[1]  >= first[1];
+    return b1 || b2;
+  }
+
+  bool overlap() const noexcept {
+    bool b1 = second[0] >= first[0] && second[0] <= first[1];
+    bool b2 = second[1] >= first[0] && second[1] <= first[1];
+    bool b3 = first[0] >= second[0] && first[0] <= second[1];
+    bool b4 = first[1] >= second[0] && first[1] <= second[1];
+    return covered() || b1 || b2 || b3 || b4;
+  }
+};
+
 std::pair<int, int> day4(line_view file);
 
 }