Skip to content

Commit

Permalink
Improved main.c
Browse files Browse the repository at this point in the history
  • Loading branch information
@fleschutz
fleschutz committed Mar 8, 2021
1 parent a91d652 commit 4ed9a69
Show file tree
Hide file tree
Showing 2 changed files with 32 additions and 27 deletions.
3 changes: 2 additions & 1 deletion README.md
View file
Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,8 @@ Installation
------------
Perform the following steps, please:
```
$ git clone https://github.com/fleschutz/LSS; cd LSS
$ git clone https://github.com/fleschutz/LSS
$ cd LSS
$ gcc -O3 -fopenmp main.c (for GCC compiler) or: clang -O3 -fopenmp main.c (for CLANG compiler)
$ ./a.out > out.txt
$ sort -g out.txt > list.txt
Expand Down
56 changes: 30 additions & 26 deletions main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3,9 +3,9 @@
#include <stdio.h>
#include <stdlib.h>

#define BigInt int64_t // or __int128_t
#define MAX_RESULTS 1000 // print only results between 0...1000
#define MAX_ROUNDS 1000000
#define BigInt int64_t // or __int128_t
#define MAX_RESULTS 1000 // print results between 0...<n>
#define MAX_ROUNDS 1000000 // use values between 0...<n>
static uint32_t numSolutions[MAX_RESULTS];

static void printNoSolutions()
Expand All @@ -16,7 +16,7 @@ static void printNoSolutions()
{
case 4:
case 5:
printf("%ld = no solution exist\n", (int64_t)n);
printf("%3ld = no solution\n", (int64_t)n);
break;
default:
break;
Expand Down Expand Up @@ -45,48 +45,50 @@ static void printSolution(BigInt n, BigInt x, BigInt y, BigInt z)

// print formatted to be: x <= y <= z
if (x <= y && y <= z)
printf("%ld = %ld³ + %ld³ + %ld³\n", (int64_t)n, (int64_t)x, (int64_t)y, (int64_t)z);
printf("%3ld = %ld³ + %ld³ + %ld³\n", (int64_t)n, (int64_t)x, (int64_t)y, (int64_t)z);
else if (x <= z && z <= y)
printf("%ld = %ld³ + %ld³ + %ld³\n", (int64_t)n, (int64_t)x, (int64_t)z, (int64_t)y);
printf("%3ld = %ld³ + %ld³ + %ld³\n", (int64_t)n, (int64_t)x, (int64_t)z, (int64_t)y);
else if (y <= x && x <= z)
printf("%ld = %ld³ + %ld³ + %ld³\n", (int64_t)n, (int64_t)y, (int64_t)x, (int64_t)z);
printf("%3ld = %ld³ + %ld³ + %ld³\n", (int64_t)n, (int64_t)y, (int64_t)x, (int64_t)z);
else if (y <= z && z <= x)
printf("%ld = %ld³ + %ld³ + %ld³\n", (int64_t)n, (int64_t)y, (int64_t)z, (int64_t)x);
printf("%3ld = %ld³ + %ld³ + %ld³\n", (int64_t)n, (int64_t)y, (int64_t)z, (int64_t)x);
else if (z <= x && x <= y)
printf("%ld = %ld³ + %ld³ + %ld³\n", (int64_t)n, (int64_t)z, (int64_t)x, (int64_t)y);
printf("%3ld = %ld³ + %ld³ + %ld³\n", (int64_t)n, (int64_t)z, (int64_t)x, (int64_t)y);
else
printf("%ld = %ld³ + %ld³ + %ld³\n", (int64_t)n, (int64_t)z, (int64_t)y, (int64_t)x);
printf("%3ld = %ld³ + %ld³ + %ld³\n", (int64_t)n, (int64_t)z, (int64_t)y, (int64_t)x);

fflush(stdout); // to disable buffering
}

static void printSolutionsByBruteForce(BigInt beginOfSearch, BigInt endOfSearch)
{
#pragma omp parallel for
for (BigInt x = beginOfSearch; x < endOfSearch; ++x)
{
BigInt *x3Ptr = &cubeNumbers[x];
for (BigInt y = 0, *y3Ptr = &cubeNumbers[0]; y <= x; ++y, ++y3Ptr)
const BigInt x3 = cubeNumbers[x];
#pragma omp parallel for
for (BigInt y = 0; y <= x; ++y)
{
for (BigInt z = 0, *z3Ptr = &cubeNumbers[0]; z <= y; ++z, ++z3Ptr)
const BigInt y3 = cubeNumbers[y];
for (BigInt z = 0; z <= y; ++z)
{
register BigInt n = *x3Ptr + *y3Ptr + *z3Ptr;
const BigInt z3 = cubeNumbers[z];
BigInt n = x3 + y3 + z3;
if (n < MAX_RESULTS)
printSolution(n, x, y, z);

n = -*x3Ptr + *y3Ptr + *z3Ptr;
n = -x3 + y3 + z3;
if (-MAX_RESULTS < n && n < MAX_RESULTS)
printSolution(n, -x, y, z);

n = *x3Ptr - *y3Ptr + *z3Ptr;
n = x3 - y3 + z3;
if (-MAX_RESULTS < n && n < MAX_RESULTS)
printSolution(n, x, -y, z);

n = *x3Ptr + *y3Ptr - *z3Ptr;
n = x3 + y3 - z3;
if (-MAX_RESULTS < n && n < MAX_RESULTS)
printSolution(n, x, y, -z);

n = *x3Ptr - *y3Ptr - *z3Ptr;
n = x3 - y3 - z3;
if (-MAX_RESULTS < n && n < MAX_RESULTS)
printSolution(n, x, -y, -z);
}
Expand All @@ -99,15 +101,17 @@ static void printSolutionsByBinarySearch(BigInt beginOfSearch, BigInt endOfSearc
#pragma omp parallel for
for (BigInt x = beginOfSearch; x < endOfSearch; ++x)
{
BigInt *x3Ptr = &cubeNumbers[x];
for (BigInt y = 0, *y3Ptr = &cubeNumbers[0]; y <= x; ++y, ++y3Ptr)
BigInt x3 = cubeNumbers[x];
for (BigInt y = 0; y <= x; ++y)
{
BigInt y3 = cubeNumbers[y];

// Binary search for: x³ - y³ - z³
BigInt min = 0, max = x;
do
{
const BigInt z = (min + max) / (BigInt)2;
const BigInt n = *x3Ptr - *y3Ptr - cubeNumbers[z];
const BigInt n = x3 - y3 - cubeNumbers[z];

if (n >= MAX_RESULTS)
max = z - 1;
Expand All @@ -126,7 +130,7 @@ static void printSolutionsByBinarySearch(BigInt beginOfSearch, BigInt endOfSearc
do
{
const BigInt z = (min + max) / (BigInt)2;
const BigInt n = *x3Ptr - *y3Ptr + cubeNumbers[z];
const BigInt n = x3 - y3 + cubeNumbers[z];

if (n >= MAX_RESULTS)
max = z - 1;
Expand All @@ -145,7 +149,7 @@ static void printSolutionsByBinarySearch(BigInt beginOfSearch, BigInt endOfSearc
do
{
const BigInt z = (min + max) / (BigInt)2;
const BigInt n = -*x3Ptr + *y3Ptr + cubeNumbers[z];
const BigInt n = -x3 + y3 + cubeNumbers[z];

if (n >= MAX_RESULTS)
max = z - 1;
Expand All @@ -169,9 +173,9 @@ int main()

preCalculateCubeNumbers();

// printSolutionsByBruteForce(0, 5000);
printSolutionsByBruteForce(0, MAX_ROUNDS);

printSolutionsByBinarySearch(0/*5000*/, MAX_ROUNDS);
//printSolutionsByBinarySearch(0/*5000*/, MAX_ROUNDS);

return 0;
}

0 comments on commit 4ed9a69

Please sign in to comment.