74 lines
1.3 KiB
C++
74 lines
1.3 KiB
C++
// Rotate a square matrix in place.
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#define CATCH_CONFIG_MAIN
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#include <catch.hpp>
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#include <fmt/format.h>
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#include <experimental/string_view>
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#include <string>
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using string_view = std::experimental::string_view;
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using image = std::array<std::array<uint32_t, 3>, 3>;
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image parse(string_view in) {
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image out;
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size_t x = 0;
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size_t y = 0;
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for (auto ch : in) {
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if (ch == ';') {
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continue;
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}
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out[y][x] = ch;
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if (++x == out[0].size()) {
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y++;
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x = 0;
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}
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}
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return out;
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}
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std::string to_string(const image& img) {
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std::string out;
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for (const auto& row : img) {
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for (auto ch : row) {
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out.push_back(char(ch));
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}
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out.push_back(';');
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}
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return out;
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}
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image rotate(image in) {
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// TODO(michaelh): image is heavy but there's no temporary to pass
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// about.
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image out;
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// TODO(michaelh): the problem says in-place. I think you can using
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// one temporary value so, for example, the flow is:
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//
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// c -> tmp
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// a -> c'
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// h -> a'
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// j -> h'
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// tmp -> j'
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//
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for (size_t y = 0; y < in.size(); y++) {
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for (size_t x = 0; x < in[0].size(); x++) {
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out[x][in.size() - y - 1] = in[y][x];
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}
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}
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return out;
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}
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TEST_CASE("cc17", "compress") {
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// abc hda
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// def --> ieb
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// hij jfc
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CHECK(to_string(rotate(parse("abcdefhij"))) == "hda;ieb;jfc;");
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}
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