add day 8 (c++)

1 files changed, 107 insertions, 0 deletions

diff --git a/day8/both.cpp b/day8/both.cpp
new file mode 100644
index 0000000..d604954
--- /dev/null
+++ b/day8/both.cpp
@@ -0,0 +1,107 @@
+#include <algorithm>
+#include <iostream>
+#include <string>
+#include <vector>
+
+int visible = 0;
+std::vector<std::string> map;
+
+bool checkTree(int x, int y)
+{
+    char c = map[y][x];
+    char v;
+
+    // Left check
+    v = '0';
+    for (int i = 0; i < x; ++i)
+        v = std::max(v, map[y][i]);
+    if (c > v)
+        return true;
+
+    // Right check
+    v = '0';
+    for (int i = map[y].size() - 1; i > x; --i)
+        v = std::max(v, map[y][i]);
+    if (c > v)
+        return true;
+
+    // North check
+    v = '0';
+    for (int i = 0; i < y; ++i)
+        v = std::max(v, map[i][x]);
+    if (c > v)
+        return true;
+
+    // South check
+    v = '0';
+    for (int i = map.size() - 1; i > y; --i)
+        v = std::max(v, map[i][x]);
+
+    return c > v;
+}
+
+int scenicScore(int x, int y)
+{
+    char c = map[y][x];
+    int n = 0, s = 0, e = 0, w = 0;
+
+    // Left check
+    for (int i = x - 1; i >= 0; --i) {
+        ++w;
+        if (c <= map[y][i])
+            break;
+    }
+
+    // Right check
+    for (int i = x + 1; i < map[y].size(); ++i) {
+        ++e;
+        if (c <= map[y][i])
+            break;
+    }
+
+    // North check
+    for (int i = y - 1; i >= 0; --i) {
+        ++n;
+        if (c <= map[i][x])
+            break;
+    }
+
+    // South check
+    for (int i = y + 1; i < map.size(); ++i) {
+        ++s;
+        if (c <= map[i][x])
+            break;
+    }
+
+    std::cout << x << ", " << y << ": " << n << ' ' << s << ' ' << e << ' ' << w << std::endl;
+    return n * s * e * w;
+}
+
+int main()
+{
+    // Consume entire input into map
+    while (!std::cin.eof()) {
+        std::string line;
+        std::getline(std::cin, line);
+        if (!std::cin.eof())
+            map.push_back(line);
+    }
+
+    visible = 2 * map[0].size() - 4 + 2 * map.size();
+    int sx, sy, sc = 0;
+
+    // For each possibly-hidden tree...
+    for (int y = 1; y < map.size() - 1; ++y) {
+        for (int x = 1; x < map[y].size() - 1; ++x) {
+            if (checkTree(x, y))
+                ++visible;
+            if (int qq = scenicScore(x, y); qq > sc)
+                sx = x, sy = y, sc = qq;
+        }
+    }
+
+    std::cout << visible << std::endl;
+    std::cout << sx << ", " << sy << ": " << sc << std::endl;
+
+    return 0;
+}