Language: C++

#pragma GCC optimize ("O3")

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <queue>
#include <set>
#include <algorithm>
#include <numeric>
#include <list>
using namespace std;

using QWORD  = uint64_t;
using SQWORD = int64_t;
using DWORD  = uint32_t;
using SDWORD = int32_t;
using WORD   = uint16_t;
using SWORD  = int16_t;
using BYTE   = uint8_t;
using SBYTE  = int8_t;
using DOUBLE = double;
using FLOAT  = float;

#define MIN_SDWORD (-2147483648)
#define MAX_SDWORD (2147483647)
#define MIN_SBYTE (-128)
#define MAX_SBYTE (127)

#define MIN_SQWORD (0x8000000000000000)
#define MAX_SQWORD (0x7FFFFFFFFFFFFFFF)

#define MAX_QWORD  (0xFFFFFFFFFFFFFFFF)
#define MAX_DWORD  (0xFFFFFFFF)
#define MAX_WORD   (0xFFFF)
#define MAX_BYTE   (0xFF)


#define ArrayLength(a)  (sizeof(a) / sizeof(a[0]))

static inline QWORD MAX(QWORD a, QWORD b) { return a > b ? a : b; }
static inline DWORD MAX(DWORD a, DWORD b) { return a > b ? a : b; }
static inline SDWORD MAX(SDWORD a, SDWORD b) { return a > b ? a : b; }
static inline QWORD MIN(QWORD a, QWORD b) { return a < b ? a : b; }
static inline DWORD MIN(DWORD a, DWORD b) { return a < b ? a : b; }
static inline SDWORD MIN(SDWORD a, SDWORD b) { return a < b ? a : b; }

#define BYTE_BITS   (8)
#define WORD_BITS   (16)
#define DWORD_BITS  (32)
#define QWORD_BITS  (64)

using M_BOOL = bool;
#define M_TRUE (true)
#define M_FALSE (false)
#define DIVISOR (1000000007)

static inline void inputString(char *pcStr)
{
    char *pcCur = pcStr;
    for (;;) {
        char c = getchar();
        if (('\n' == c) || (EOF == c)) {
            break;
        }
        *pcCur = c;
        pcCur++;
    }
    *pcCur = '\0';
}


static inline SQWORD inputSQWORD(void)
{
    SQWORD sqNumber = 0;
    SQWORD sqMultiplier = 1;
    M_BOOL bRead = M_FALSE;
    for (;;) {
        char c = getchar();
        if (!bRead) {
            if ('-' == c) {
                sqMultiplier = -1;
            }
        }
        if (('0' <= c) && (c <= '9')) {
            sqNumber *= 10LL;
            sqNumber += (SQWORD)(c - '0');
            bRead = M_TRUE;
        } else {
            if (bRead) {
                return sqNumber * sqMultiplier;
            }
        }
    }
}


static inline SDWORD inputSDWORD(void)
{
    SDWORD lNumber = 0;
    SDWORD lMultiplier = 1;
    M_BOOL bRead = M_FALSE;
    for (;;) {
        char c = getchar();
        if (!bRead) {
            if ('-' == c) {
                lMultiplier = -1;
            }
        }
        if (('0' <= c) && (c <= '9')) {
            lNumber *= 10;
            lNumber += (c - '0');
            bRead = M_TRUE;
        } else {
            if (bRead) {
                return lNumber * lMultiplier;
            }
        }
    }
}

static inline DOUBLE inputFP(void)
{
    DOUBLE dInt = 0.0;
    DOUBLE dFrac = 0.0;
    DOUBLE dMultiplier = 1.0;
    DWORD dwFpCnt = 0;
    DOUBLE *pdCur = &dInt;
    M_BOOL bRead = M_FALSE;
    for (;;) {
        char c = getchar();
        if (!bRead) {
            if ('-' == c) {
                dMultiplier = -1;
            }
        }
        if ('.' == c) {
            pdCur = &dFrac;
        } else if (('0' <= c) && (c <= '9')) {
            (*pdCur) *= 10;
            (*pdCur) += (DOUBLE)(c - '0');
            bRead = M_TRUE;
            if (pdCur == &dFrac) {
                dwFpCnt++;
            }
        } else {
            if (bRead) {
                return dMultiplier * (dInt + dFrac / (pow((DOUBLE)10.0 , (DOUBLE)dwFpCnt)));
            }
        }
    }
}


/**
 *  mod による操作ライブラリ
 */

#define ANS_MOD (1000000007LL)
 
static SQWORD addMod(SQWORD x, SQWORD y)
{ 
    return (x + y) % ANS_MOD;
}
 
static SQWORD subMod(SQWORD x, SQWORD y)
{
    return (x - y + ANS_MOD) % ANS_MOD;
}
 
static SQWORD mulMod(SQWORD x, SQWORD y) 
{
    return (x * y) % ANS_MOD;
}
 
static SQWORD powMod(SQWORD x, SQWORD e) {
    SQWORD v = 1;
    for (; e; x = mulMod(x, x), e >>= 1) {
        if (e & 1) {
            v = mulMod(v, x);
        }
    }
    return v;
}
 
static SQWORD divMod(SQWORD x, SQWORD y)
{
    return mulMod(x, powMod(y, ANS_MOD - 2));
}
 
 
static SQWORD combMod(SQWORD n, SQWORD k)
{
    SQWORD v=1;
    for(SQWORD i=1; i<=k; i++) {
        v = divMod(mulMod(v, n-i+1),i);
    } 
    return v;
}


int main(void)
{
    SQWORD sqInput_N = inputSQWORD();
    SQWORD sqInput_K = inputSQWORD();

    DOUBLE dAns = 0.0;

    /* 1回 */
    dAns += (DOUBLE)(max(sqInput_N - sqInput_K + 1, 0LL)) / (DOUBLE)sqInput_N;

    SQWORD sqDivisor1 = 1;
    SQWORD sqDivisor2 = 2;
    DOUBLE dMultiplier = (DOUBLE)(0.5);
    for (SDWORD lTrial = 0; lTrial <= 10000000; lTrial++) {
        SQWORD sqUpper = (sqInput_K-1) / sqDivisor1;
        SQWORD sqLower = (sqInput_K-1) / sqDivisor2;

//        printf("%lld %lld %lld\n", sqUpper, sqLower, sqInput_N);

        dAns += (DOUBLE)(min(sqUpper, sqInput_N) - min(sqLower, sqInput_N)) * dMultiplier / (DOUBLE)sqInput_N;

        sqDivisor1 *= 2;
        sqDivisor2 *= 2;
        dMultiplier /= 2;

        if (sqUpper == sqLower) {
            break;
        }
    }
    printf("%0.11llf\n", dAns);

    return 0;
}

Compiler output:
a.cc:19:16: error: 'uint64_t' does not name a type
   19 | using QWORD  = uint64_t;
      |                ^~~~~~~~
a.cc:17:1: note: 'uint64_t' is defined in header '<cstdint>'; this is probably fixable by adding '#include <cstdint>'
   16 | #include <list>
  +++ |+#include <cstdint>
   17 | using namespace std;
a.cc:21:16: error: 'uint32_t' does not name a type
   21 | using DWORD  = uint32_t;
      |                ^~~~~~~~
a.cc:21:16: note: 'uint32_t' is defined in header '<cstdint>'; this is probably fixable by adding '#include <cstdint>'
a.cc:23:16: error: 'uint16_t' does not name a type
   23 | using WORD   = uint16_t;
      |                ^~~~~~~~
a.cc:23:16: note: 'uint16_t' is defined in header '<cstdint>'; this is probably fixable by adding '#include <cstdint>'
a.cc:25:16: error: 'uint8_t' does not name a type
   25 | using BYTE   = uint8_t;
      |                ^~~~~~~
a.cc:25:16: note: 'uint8_t' is defined in header '<cstdint>'; this is probably fixable by adding '#include <cstdint>'
a.cc:46:15: error: 'QWORD' does not name a type; did you mean 'SWORD'?
   46 | static inline QWORD MAX(QWORD a, QWORD b) { return a > b ? a : b; }
      |               ^~~~~
      |               SWORD
a.cc:47:15: error: 'DWORD' does not name a type; did you mean 'SWORD'?
   47 | static inline DWORD MAX(DWORD a, DWORD b) { return a > b ? a : b; }
      |               ^~~~~
      |               SWORD
a.cc:49:15: error: 'QWORD' does not name a type; did you mean 'SWORD'?
   49 | static inline QWORD MIN(QWORD a, QWORD b) { return a < b ? a : b; }
      |               ^~~~~
      |               SWORD
a.cc:50:15: error: 'DWORD' does not name a type; did you mean 'SWORD'?
   50 | static inline DWORD MIN(DWORD a, DWORD b) { return a < b ? a : b; }
      |               ^~~~~
      |               SWORD
a.cc: In function 'DOUBLE inputFP()':
a.cc:132:5: error: 'DWORD' was not declared in this scope; did you mean 'SWORD'?
  132 |     DWORD dwFpCnt = 0;
      |     ^~~~~
      |     SWORD
a.cc:149:17: error: 'dwFpCnt' was not declared in this scope
  149 |                 dwFpCnt++;
      |                 ^~~~~~~
a.cc:153:82: error: 'dwFpCnt' was not declared in this scope
  153 |                 return dMultiplier * (dInt + dFrac / (pow((DOUBLE)10.0 , (DOUBLE)dwFpCnt)));
      |                                                                                  ^~~~~~~
a.cc: In function 'int main()':
a.cc:215:25: error: no matching function for call to 'max(SQWORD, long long int)'
  215 |     dAns += (DOUBLE)(max(sqInput_N - sqInput_K + 1, 0LL)) / (DOUBLE)sqInput_N;
      |                      ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/14/string:51,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:3:
/usr/include/c++/14/bits/stl_algobase.h:257:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note:   template argument deduction/substitution failed:
a.cc:215:25: note:   deduced conflicting types for parameter 'const _Tp' ('long int' and 'long long int')
  215 |     dAns += (DOUBLE)(max(sqInput_N - sqInput_K + 1, 0LL)) / (DOUBLE)sqInput_N;
      |                      ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61,
                 from a.cc:14:
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:215:25: note:   mismatched types 'std::initializer_list<_Tp>' and 'long int'
  215 |     dAns += (DOUBLE)(max(sqInput_N - sqInput_K + 1, 0LL)) / (DOUBLE)sqInput_N;
      |                      ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~