#include #include #include #include using namespace std; typedef vector> Input; Input parse() { Input data; for (string line; getline(cin, line);) { auto i = vector(line.begin(), line.end()); for_each(i.begin(), i.end(), [](unsigned char &x){ x -= '0'; }); data.push_back(i); } return data; } unsigned p1(const Input &trees) { int height = trees.size(); int width = trees.front().size(); // C++ is nice except when it isn't bool (*vis)[width] = (bool (*)[width])new bool[width * height]; memset(vis, 0, sizeof(bool) * width * height); // The corners are visible vis[0][0] = true; vis[height - 1][0] = true; vis[0][width - 1] = true; vis[height - 1][width - 1] = true; // Determine visibility from all four directions for (int y = 1; y < height - 1; y++) { for (int last = -1, x = 0; x < width; x++) { if (trees[y][x] <= last) continue; last = trees[y][x]; vis[y][x] = true; } for (int last = -1, x = width - 1; x >= 0; x--) { if (trees[y][x] <= last) continue; last = trees[y][x]; vis[y][x] = true; } } for (int x = 1; x < width - 1; x++) { for (int last = -1, y = 0; y < height; y++) { if (trees[y][x] <= last) continue; last = trees[y][x]; vis[y][x] = true; } for (int last = -1, y = height - 1; y >= 0; y--) { if (trees[y][x] <= last) continue; last = trees[y][x]; vis[y][x] = true; } } // Count 'em up unsigned count = 0; for (int y = 0; y < height; y++) { for (int x = 0; x < width; x++) if (vis[y][x]) count++; } // Debug //for (int y = 0; y < height; y++) { //for (int x = 0; x < width; x++) clog << (char)(vis[y][x] ? 'x' : ' '); //clog << endl; //} delete vis; return count; } unsigned p2(const Input &trees) { int height = trees.size(); int width = trees.front().size(); unsigned score = 0; for (int y = 1; y < height - 1; y++) { for (int x = 1; x < width - 1; x++) { unsigned tree = trees[y][x]; // Check all four directions unsigned cur = 1; unsigned c; c = 1; for (int ny = y + 1; ny < height - 1 && trees[ny][x] < tree; ny++) c++; cur *= c; c = 1; for (int ny = y - 1; ny > 0 && trees[ny][x] < tree; ny--) c++; cur *= c; c = 1; for (int nx = x + 1; nx < height - 1 && trees[y][nx] < tree; nx++) c++; cur *= c; c = 1; for (int nx = x - 1; nx > 0 && trees[y][nx] < tree; nx--) c++; cur *= c; if (cur > score) score = cur; } } return score; } int main() { auto input = parse(); cout << p1(input) << endl; cout << p2(input) << endl; }