highest_bit.md

位运算——取最高位

int highBit(unsigned int n) {
    n |= n >> 1;
    n |= n >> 2;
    n |= n >> 4;
    n |= n >> 8;
    n |= n >> 16;
    return 31 - __builtin_clz((n + 1) >> 1);
}

31 - bits.LeadingZeros32(uint32(n))

31 - Integer.numberOfLeadingZeros(k - 1);