#include #include #include /** * 883. Projection Area of 3D Shapes * You are given an n x n grid where we place some 1 x 1 x 1 cubes that are axis-aligned with the x, y, and z axes. * Each value v = grid[i][j] represents a tower of v cubes placed on top of the cell (i, j). * We view the projection of these cubes onto the xy, yz, and zx planes. * A projection is like a shadow, that maps our 3-dimensional figure to a 2-dimensional plane. We are viewing the "shadow" when looking at the cubes from the top, the front, and the side. * Return the total area of all three projections. */ class Solution { public: static int projectionArea(const std::vector>& G) { const int n = G.size(); int xy = 0, yz = 0, zx = 0; std::for_each(G.begin(), G.end(), [&](const std::vector& v) { xy += std::count_if(v.begin(), v.end(), [](int x) { return x > 0; }); zx += *std::max_element(v.begin(), v.end()); }); for (int i = 0; i < n; ++i) { int t = 0; for (int j = 0; j < n; ++j) { t = std::max(t, G[j][i]); } yz += t; } return xy + yz + zx; } };