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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
static int debug = 0;
typedef uint32_t word_t;
enum { WORD_BITS = sizeof(word_t) * 8 };
static inline int bindex(int b) { return b / WORD_BITS; }
static inline int boffset(int b) { return b % WORD_BITS; }
static inline void set_bit(word_t *bits, int b)
{
bits[bindex(b)] |= (1 << (boffset(b)));
}
static inline int get_bit(word_t *bits, int b)
{
return ((bits[bindex(b)] & (1 << (boffset(b)))) >> (boffset(b)));
}
typedef struct _Item
{
int value;
int weight;
} Item;
typedef struct _SolverData {
int v;
word_t *bits;
} SolverData;
typedef struct _Solver
{
int k; // capacity
int n; // items #
int nw; // # bytes per bits array
int sum_w; // sum of item weight
size_t sd_sz; // solver data size
Item *items; // items
SolverData *data; // solver data
} Solver;
static void solve(Solver* solver)
{
int n, k, nw;
size_t sd_sz;
int i, j;
int v, w;
int max_c, upper_bound;
char *data_base;
Item *item;
SolverData *c, *p;
max_c = solver->sum_w;
sd_sz = solver->sd_sz;
nw = solver->nw;
n = solver->n;
k = solver->k;
item = solver->items;
data_base = (char *) solver->data;
/* SOLVE */
for (i = 0; i < n; i++, item++)
{
v = item->value;
w = item->weight;
c = (SolverData *) (data_base + (sd_sz * k));
p = (SolverData *) (data_base + (sd_sz * (k - w)));
max_c -= w;
upper_bound = (((k - max_c) > w) ? (k - max_c) : w );
for (j = k; j >= upper_bound; j--)
{
if (j < w)
break;
if ((j >= w) && (c->v < (v + p->v)))
{
c->v = v + p->v;
memcpy(c->bits, p->bits, (nw * sizeof(word_t)));
set_bit(c->bits, i);
}
c = (SolverData *) (((char *) c) - sd_sz);
p = (SolverData *) (((char *) p) - sd_sz);
}
if (debug)
{
printf("i=% 4d : ", i);
for (j = 0; j <= k; j++)
{
c = (SolverData *) (data_base + (sd_sz * j));
printf("% 4d ", c->v);
}
printf("\n");
}
}
}
static void print(Solver* solver)
{
int b;
int i;
int v, w;
Item *item;
SolverData *sol;
v = 0;
w = 0;
sol = (SolverData *) (((char *) solver->data) + (solver->sd_sz * solver->k));
item = solver->items;
printf("%d %d\n", sol->v, 0);
for (i = 0; i < solver->n; i++, item++)
{
b = get_bit(sol->bits, i);
printf("%d ", b);
if (b)
{
v += item->value;
w += item->weight;
}
}
printf("\n");
if (v != sol->v)
fprintf(stderr, "ERROR: value %d != %d\n", v, sol->v);
if (w > solver->k)
fprintf(stderr, "ERROR: weight %d > %d\n", w, solver->k);
}
int main(int argc, char** argv, char** env)
{
FILE *fp;
Solver solver; // solver
int i;
Item *item;
SolverData *data;
if(argc < 2)
{
fprintf(stderr,"input file missing\n");
return EXIT_FAILURE;
}
if (debug) printf("%s read %s\n", argv[0], argv[1]);
fp = fopen(argv[1], "r");
if (fp == NULL)
{
fprintf(stderr, "I couldn't open results.dat for reading.\n");
exit(EXIT_FAILURE);
}
/* read k and n */
if (fscanf(fp, "%d %d\n", &solver.n, &solver.k) != 2)
{
fprintf(stderr, "ERROR: read first line\n");
return EXIT_FAILURE;
}
if (debug) printf(" K:%d N:%d\n", solver.k, solver.n);
/* allocate */
solver.items = calloc(solver.n, sizeof(Item));
if (!solver.items)
{
fprintf(stderr, "ERROR: items calloc\n");
return EXIT_FAILURE;
}
solver.nw = (solver.n / WORD_BITS + 1);
solver.sd_sz = sizeof(SolverData) + (solver.nw * sizeof(word_t));
solver.data= calloc((solver.k + 1), solver.sd_sz);
if (!solver.data)
{
free(solver.items);
fprintf(stderr, "ERROR: solver calloc\n");
return EXIT_FAILURE;
}
for (i = 0; i <= solver.k; i++)
{
data = (SolverData *) (((char *) solver.data) + solver.sd_sz * i);
data->bits = (word_t *) (((char *) data) + sizeof(SolverData));
}
/* read items */
solver.sum_w = 0;
item = solver.items;
for (i = 0; i < solver.n; i++, item++)
{
fscanf(fp, "%d %d\n", &item->value, &item->weight);
solver.sum_w += item->weight;
}
fclose(fp);
if (debug)
{
item = solver.items;
printf(" index value weight\n");
for (i = 0; i < solver.n; i++, item++)
printf(" % 8d % 8d % 8d\n", i, item->value, item->weight);
}
solve(&solver);
print(&solver);
free(solver.items);
free(solver.data);
return EXIT_SUCCESS;
}
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