2019 day7 part1

1 files changed, 60 insertions, 0 deletions

diff --git a/src/2019/day7/aoc.cpp b/src/2019/day7/aoc.cpp
index 593848b..c1a8ba5 100644
--- a/src/2019/day7/aoc.cpp
+++ b/src/2019/day7/aoc.cpp
@@ -1,4 +1,64 @@
 #include "aoc.h"
+#include "../day5/aoc.h"
+#include <set>
 
 namespace aoc2019 {
+
+void find_max(int* is, int i, std::set<int>& ns, int* max, const std::vector<int>& codes) {
+  if (i == 10) {
+    set_computer(&is[i - 2]);
+    int n = run_computer(codes);
+    if (n > *max) {
+      *max = n;
+    }
+  } else {
+    for (int x : {0, 1, 2, 3, 4}) {
+      if (ns.find(x) != ns.end()) {
+        continue;
+      } else {
+        is[i] = x;
+        if (i > 0) {
+          set_computer(&is[i - 2]);
+          is[i + 1] = run_computer(codes);
+        }
+        ns.insert(x);
+        find_max(is, i + 2, ns, max, codes);
+        ns.erase(x);
+      }
+    }
+  }
+}
+
+static void get_number(const char** pp, int* d) {
+  const char* p = *pp;
+  int sign = 1;
+  if (*p == '-') {
+    sign = -1;
+    p++;
+  }
+  while (*p >= '0' && *p <= '9') {
+    *d = *d * 10 + *p - '0';
+    p++;
+  }
+  *d *= sign;
+  *pp = p;
+}
+
+int day7(line_view file) {
+  int max{INT32_MIN};
+  int is[10] = {0};
+  std::set<int> ns;
+  std::vector<int> codes;
+  const char* p = file.line;
+  while (p < file.line + file.length) {
+    if ((*p >= '0' && *p <= '9') || *p == '-') {
+      int d{0};
+      get_number(&p, &d);
+      codes.push_back(d);
+    }
+    p++;
+  }
+  find_max(is, 0, ns, &max, codes);
+  return max;
 }
+} // namespace aoc2019