qnighy https://blog.hatena.ne.jp/qnighy/ 簡潔なQ https://qnighy.hatenablog.com/ Programming C ビットを数える・探すアルゴリズムのpopcountをちょっと改変すればいいだけやんけ。 #include <stdio.h> unsigned int bitreverse(unsigned int x) { x = (x & 0x55555555)<<1 | (x & 0xaaaaaaaa)>>1; x = (x & 0x33333333)<<2 | (x & 0xcccccccc)>>2; x = (x & 0x0f0f0f0f)<<4 | (x & 0xf0f0f0f0)>>4; x = (x & 0x00ff00ff)<<8 | (x & 0xff00ff00)>>8; x = (x … 190 <iframe src="https://hatenablog-parts.com/embed?url=https%3A%2F%2Fqnighy.hatenablog.com%2Fentry%2F20091006%2F1254832950" title="ビットリバース - 簡潔なQ" class="embed-card embed-blogcard" scrolling="no" frameborder="0" style="display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;"></iframe> Hatena Blog https://hatena.blog 2009-10-06 21:42:30 rich https://qnighy.hatenablog.com/entry/20091006/1254832950 1.0 100%