My goal here is to find all possible combinations that sums to a given total. For example, if the array is 2 59 3 43 5 9 8 62 10 4 and if the total is 12, then possible combinations are
2 10
3 9
8 4
5 3 4
Here is the first set of code, that I've written. Wondering the best improvements that can be done on this.
int find_numbers_matching_sum(int *number_coll, int total)
{
int *search_till = lower_bound(number_coll,number_coll+TOTAL_SIZE, total);
int location = search_till - number_coll;
if (*search_till > total && location > 0 )
{
--location;
}
while ( location >= 0 )
{
find_totals(number_coll,total,location);
--location;
}
return 1;
}
int find_totals(int *number_coll, int total, int end_location)
{
int left_ones = total - number_coll[end_location];
int curloc = end_location;
int *search_till = 0;
int location ;
int all_numbers[10];
int i = 0;
all_numbers[i] = number_coll[end_location];
while ( left_ones && curloc >= 0 )
{
search_till = lower_bound(number_coll,number_coll+end_location, left_ones);
location = search_till - number_coll;
if (*search_till > left_ones && location > 0 )
{
--location;
}
else if ( left_ones < *search_till )
{
break;
}
curloc=location;
left_ones = left_ones - number_coll[curloc];
all_numbers[++i] = number_coll[curloc];
end_location = curloc - 1;
}
if ( !left_ones )
{
while ( i>=0)
{
cout << all_numbers[i--] << ' ';
}
}
cout << endl;
return 1;
}
#include <iostream>
#include <vector>
using namespace std;
struct State {
int v;
const State *rest;
void dump() const {
if(rest) {
cout << ' ' << v;
rest->dump();
} else {
cout << endl;
}
}
State() : v(0), rest(0) {}
State(int _v, const State &_rest) : v(_v), rest(&_rest) {}
};
void ss(int *ip, int *end, int target, const State &state) {
if(target < 0) return; // assuming we don't allow any negatives
if(ip==end && target==0) {
state.dump();
return;
}
if(ip==end)
return;
{ // without the first one
ss(ip+1, end, target, state);
}
{ // with the first one
int first = *ip;
ss(ip+1, end, target-first, State(first, state));
}
}
int main() {
int a[] = { 2,59,3,43,5,9,8,62,10,4 };
int * start = &a[0];
int * end = start + sizeof(a) / sizeof(a[0]);
ss(start, end, 12, State());
}