long long int countNumSet(int arr[], int lastInd, int numChoose, int remainder, int modNum,
long long int memoTable[][MAX_CHOOSE_SIZE + 1][MAX_MOD])
{
int r, nextR;
if(numChoose == 0)
{
if(remainder == 0)
return 1;
return 0;
}
/* Base cases */
if(lastInd + 1 < numChoose)
return 0; /* Cannot choose numChoose numbers */
if(memoTable[lastInd][numChoose][remainder] >= 0)
return memoTable[lastInd][numChoose][remainder];
long long int numSet = 0;
/* Not taking this element */
numSet += countNumSet(arr, lastInd - 1, numChoose, remainder, modNum, memoTable);
/* Choose this element */
r = getRemainder(arr[lastInd], modNum);
nextR = remainder - r;
if(nextR < 0)
nextR = modNum + nextR;
numSet += countNumSet(arr, lastInd - 1, numChoose - 1, nextR, modNum, memoTable);
memoTable[lastInd][numChoose][remainder] = numSet;
return numSet;
}
static int fcubes(BigInteger *pArgument)
{
int mod18, modulus, i, mod83, mask;
int pow, exp;
boolean converted = FALSE;
CopyBigInt(&value, pArgument);
// Compute argument mod 18.
mod18 = getRemainder(pArgument, 18);
if (mod18 == 4 || mod18 == 5 || mod18 == 13 || mod18 == 14)
{
return -1; // Applet does not work if the number is congruent to 4 or 5 (mod 9)
}
if (mod18 == 16)
{ // Change sign.
converted = TRUE;
BigIntNegate(&value, &value);
}
for (i = 0; i<(int)(sizeof(sums)/sizeof(sums[0])); i += 10)
{
modulus = sums[i];
if ((getRemainder(&value, modulus) + modulus)% modulus == sums[i + 1])
{
break;
}
}
if (i<(int)(sizeof(sums) / sizeof(sums[0])))
{
subtractdivide(&value, sums[i + 1], modulus); // value <- (value-sums[i+1])/modulus
multadd(&Base1, sums[i + 2], &value, sums[i + 3]); // Base1 <- sums[i+2]*value+sums[i+3]
multadd(&Base2, sums[i + 4], &value, sums[i + 5]); // Base2 <- sums[i+4]*value+sums[i+5]
multadd(&Base3, sums[i + 6], &value, sums[i + 7]); // Base3 <- sums[i+6]*value+sums[i+7]
multadd(&Base4, sums[i + 8], &value, sums[i + 9]); // Base4 <- sums[i+8]*value+sums[i+9]
}
else if (getRemainder(&value, 54) == 2)
{ // If value == 2 (mod 54)...
subtractdivide(&value, 2, 54); // value <- (value-2)/54
EvaluateQuadraticPoly(&Base1, &value, 29484, 2211, 43);
EvaluateQuadraticPoly(&Base2, &value, -29484, -2157, -41);
EvaluateQuadraticPoly(&Base3, &value, 9828, 485, 4);
EvaluateQuadraticPoly(&Base4, &value, -9828, -971, -22);
}
else if (getRemainder(&value, 83 * 108) == 83*46)
{ // If value == 83*46 (mod 83*108)...
subtractdivide(&value, 83*46, 83*108); // value <-(value - (83*46)) / (83*108)
EvaluateQuadraticPoly(&Base1, &value, 29484, 25143, 5371);
EvaluateQuadraticPoly(&Base2, &value, -29484, -25089, -5348);
EvaluateQuadraticPoly(&Base3, &value, 9828, 8129, 1682);
EvaluateQuadraticPoly(&Base4, &value, -9828, -8615, -1889);
}
else
{
// Perform Pell solution of Demjanenko's theorem
// Using these values of P, Q, R and S, a and b will be
// always one and zero (mod 6) respectively.
// P <- -112488782561 = -(52*2^31+819632865)
// Q <- -6578430178320 = -(3063*2^31+687764496)
// R <- -1923517596 = -(0*2^31+1923517596)
// S <- P
// P1 <- 1
// Q1 <- 0
// R1 <- 0
// S1 <- 1
P.limbs[1].x = S.limbs[1].x = 52;
P.limbs[0].x = S.limbs[0].x = 819632865;
Q.limbs[1].x = 3063;
Q.limbs[0].x = 687764496;
R.limbs[1].x = 0;
R.limbs[0].x = 1923517596;
P.nbrLimbs = Q.nbrLimbs = R.nbrLimbs = S.nbrLimbs = 3;
P.sign = Q.sign = R.sign = S.sign = SIGN_NEGATIVE;
P1.limbs[0].x = S1.limbs[0].x = 1;
Q1.limbs[0].x = R1.limbs[0].x = 0;
P1.nbrLimbs = Q1.nbrLimbs = R1.nbrLimbs = S1.nbrLimbs = 1;
P1.sign = Q1.sign = R1.sign = S1.sign = SIGN_POSITIVE;
mod83 = getRemainder(&value, 83);
pow = 71;
exp = 0;
while (pow != mod83)
{
exp++;
pow = (pow * 50) % 83;
}
if (exp > 82 / 2)
{
exp = 82 - exp;
Q.sign = R.sign = SIGN_POSITIVE;
} // Now exp is in range 0-41.
mask = 32;
while (mask > 0)
{
// tmpP1 <- P1*P1 + Q1*R1
// tmpQ1 <- (P1+S1) * Q1
// tmpR1 <- (P1+S1) * R1
// tmpS1 <- S1*S1 + Q1*R1
// P1 <- tmpP1
// Q1 <- tmpQ1
// R1 <- tmpR1
// S1 <- tmpS1
(void)BigIntMultiply(&P1, &P1, &tmpP1);
(void)BigIntMultiply(&Q1, &R1, &tmpQ1);
(void)BigIntMultiply(&S1, &S1, &tmpS1);
BigIntAdd(&P1, &S1, &tmpR1);
BigIntAdd(&tmpP1, &tmpQ1, &P1);
BigIntAdd(&tmpS1, &tmpQ1, &S1);
(void)BigIntMultiply(&tmpR1, &Q1, &Q1);
(void)BigIntMultiply(&tmpR1, &R1, &R1);
if ((exp & mask) != 0)
{
// tmpP1 <- P*P1 + Q*R1
// tmpQ1 <- P*Q1 + Q*S1
// tmpR1 <- R*P1 + S*R1
// tmpS1 <- R*Q1 + S*S1
// P1 <- tmpP1
// Q1 <- tmpQ1
// R1 <- tmpR1
// S1 <- tmpS1
(void)BigIntMultiply(&P, &P1, &tmpP1);
(void)BigIntMultiply(&Q, &R1, &tmpQ1);
(void)BigIntMultiply(&R, &P1, &tmpR1);
(void)BigIntMultiply(&S, &R1, &tmpS1);
BigIntAdd(&tmpP1, &tmpQ1, &P1);
BigIntAdd(&tmpR1, &tmpS1, &R1);
(void)BigIntMultiply(&P, &Q1, &tmpP1);
(void)BigIntMultiply(&Q, &S1, &tmpQ1);
(void)BigIntMultiply(&R, &Q1, &tmpR1);
(void)BigIntMultiply(&S, &S1, &tmpS1);
BigIntAdd(&tmpP1, &tmpQ1, &Q1);
BigIntAdd(&tmpR1, &tmpS1, &S1);
}
mask >>= 1;
}
addmult(&a, &P1, -3041, &Q1, -52); // a <- -3041*P1 - 52*Q1
addmult(&b, &R1, -3041, &S1, -52); // b <- -3041*R1 - 52*S1
addmult(&Base1, &a, 27, &b, -928); // Base1 <- 27*a - 928*b
addmult(&Base2, &a, -9, &b, -602); // Base2 <- -9*a - 602*b
addmult(&Base3, &a, 25, &b, -2937); // Base3 <- 25*a - 2937*b
addmult(&Base4, &a, -19, &b, 2746); // Base4 <- -19*a - 2746*b
// a <- (value - Base1^3 - Base2^3 - Base3^3 - Base4^3)/(18*83)
getSumOfCubes(); // tmpP1 = Base1^3 + Base2^3 + Base3^3 + Base4^3
BigIntSubt(&value, &tmpP1, &a);
subtractdivide(&a, 0, 18 * 83); // Divide a by 18*83.
multint(&tmpP1, &a, 10); // Base1 <- Base1 + 10*a
BigIntAdd(&tmpP1, &Base1, &Base1);
multint(&tmpP1, &a, -19); // Base2 <- Base2 - 19*a
BigIntAdd(&tmpP1, &Base2, &Base2);
multint(&tmpP1, &a, -24); // Base3 <- Base3 - 24*a
BigIntAdd(&tmpP1, &Base3, &Base3);
multint(&tmpP1, &a, 27); // Base4 <- Base4 + 27*a
BigIntAdd(&tmpP1, &Base4, &Base4);
}
if (converted != 0)
{
BigIntNegate(&Base1, &Base1);
BigIntNegate(&Base2, &Base2);
BigIntNegate(&Base3, &Base3);
BigIntNegate(&Base4, &Base4);
}
// Sort cubes
SortBigIntegers(&Base1, &Base2);
SortBigIntegers(&Base1, &Base3);
SortBigIntegers(&Base1, &Base4);
SortBigIntegers(&Base2, &Base3);
SortBigIntegers(&Base2, &Base4);
SortBigIntegers(&Base3, &Base4);
// Validate
getSumOfCubes(); // tmpP1 = Base1^3 - Base2^3 - Base3^3 - Base4^3
BigIntSubt(&tmpP1, pArgument, &tmpQ1);
if (tmpQ1.nbrLimbs != 1 || tmpQ1.limbs[0].x != 0)
{
return 1; // Result does not validate.
}
return 0;
}
