programming-examples/c/Search_Sorting/C Program to Generate All the Set Partitions of n Numbers Begining from 1 and so on.c

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2019-11-15 12:59:38 +01:00
#include <stdio.h>
#include <stdlib.h>
typedef struct
{
int first;
int n;
int level;
} Call;
void print(int n, int * a)
{
int i ;
for (i = 0; i <= n; i++)
{
printf("%d", a[i]);
}
printf("\n");
}
void integerPartition(int n, int * a)
{
int first;
int i;
int top = 0;
int level = 0;
Call * stack = (Call * ) malloc (sizeof(Call) * 1000);
stack[0].first = -1;
stack[0].n = n;
stack[0].level = level;
while (top >= 0)
{
first = stack[top].first;
n = stack[top].n;
level = stack[top].level;
if (n >= 1)
{
if (first == - 1)
{
a[level] = n;
print(level, a);
first = (level == 0) ? 1 : a[level-1];
i = first;
}
else
{
i = first;
i++;
}
if (i <= n / 2)
{
a[level] = i;
stack[top].first = i;
top++;
stack[top].first = -1;
stack[top].n = n - i;
stack[top].level = level + 1;
}
else
{
top--;
}
}
else
{
top --;
}
}
}
int main()
{
int N = 1;
int * a = (int * ) malloc(sizeof(int) * N);
int i;
printf("\nEnter a number N to generate all set partition from 1 to N: ");
scanf("%d", &N);
for ( i = 1; i <= N; i++)
{
printf("\nInteger partition for %d is: \n", i);
integerPartition (i, a);
}
return(0);
}