day1

5 files changed, 50 insertions, 5 deletions

diff --git a/src/2015/day1/README.md b/src/2015/day1/README.md
index 98b59a6..cf9151a 100644
--- a/src/2015/day1/README.md
+++ b/src/2015/day1/README.md
@@ -22,3 +22,14 @@ For example:
 
 To what floor do the instructions take Santa?
 
+--- Part Two ---
+
+Now, given the same instructions, find the position of the first character that causes him to enter the basement (floor -1). The first character in the instructions has position 1, the second character has position 2, and so on.
+
+For example:
+
+    ) causes him to enter the basement at character position 1.
+    ()()) causes him to enter the basement at character position 5.
+
+What is the position of the character that causes Santa to first enter the basement?
+
diff --git a/src/2015/day1/aoc.cpp b/src/2015/day1/aoc.cpp
index 2263558..4a4d4fc 100644
--- a/src/2015/day1/aoc.cpp
+++ b/src/2015/day1/aoc.cpp
@@ -5,9 +5,38 @@ namespace aoc2015 {
 int day1(line_view lv) {
   int level = 0;
   for (size_t i = 0; i < lv.length; ++i) {
-    level += lv.line[i] == '(' ? 1 : -1;
+    switch (lv.line[i]) {
+    case '(':
+      level += 1;
+      break;
+    case ')':
+      level += -1;
+      break;
+    default:
+      break;
+    }
   }
   return level;
 }
 
+int day1(line_view lv, int target) {
+  int level = 0;
+  for (size_t i = 0; i < lv.length; ++i) {
+    switch (lv.line[i]) {
+    case '(':
+      level += 1;
+      break;
+    case ')':
+      level += -1;
+      break;
+    default:
+      break;
+    }
+    if (level == target) {
+      return i + 1;
+    }
+  }
+  return -1;
+}
+
 } // namespace aoc2015
diff --git a/src/2015/day1/aoc.h b/src/2015/day1/aoc.h
index b83b525..af68f6a 100644
--- a/src/2015/day1/aoc.h
+++ b/src/2015/day1/aoc.h
@@ -5,5 +5,6 @@
 namespace aoc2015 {
 
 int day1(line_view lv);
+int day1(line_view lv, int target);
 
 }
diff --git a/test/test_2015.cpp b/test/test_2015.cpp
index 67e25f0..7955ede 100644
--- a/test/test_2015.cpp
+++ b/test/test_2015.cpp
@@ -1,5 +1,9 @@
 #include "catch.hpp"
+#include "2015/day1/aoc.h"
+#include <stdio.h>
 
-TEST_CASE("", "[]") {
-
+TEST_CASE("Not Quite Lisp", "[]") {
+  line_view lv = load_file("../src/2015/day1/input");
+  REQUIRE(aoc2015::day1(lv) == 74);
+  REQUIRE(aoc2015::day1(lv, -1) == 1795);
 }
diff --git a/test/test_common.cpp b/test/test_common.cpp
index 141398b..851bef7 100644
--- a/test/test_common.cpp
+++ b/test/test_common.cpp
@@ -2,8 +2,8 @@
 #include "common.h"
 
 TEST_CASE("load file", "[]") {
-  line_view file{"\n\n111\n2222\n33333\n", 17};
-  const char* lines[] = {"\n", "\n", "111\n", "2222\n", "33333\n"};
+  line_view file{"\n111\n2222\n33333\n\n", 17};
+  const char* lines[] = {"\n", "111\n", "2222\n", "33333\n", "\n"};
   int i = 0;
   per_line(
       file,