print all permutations of a given string. A permutation, also called an “arrangement number” or “order,” is a rearrangement of the elements of an ordered list S into a one-to-one correspondence with S itself. A string of length n has n! permutation.
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# include <stdio.h>
void swap (char *x, char *y)
{
char temp;
temp = *x;
*x = *y;
*y = temp;
}
void permute(char *a, int i, int n)
{
int j;
if (i == n)
printf("%s\n", a);
else
{
for (j = i; j <= n; j++)
{
swap((a+i), (a+j));
permute(a, i+1, n);
swap((a+i), (a+j));
}
}
}
int main()
{
char a[] = "ABC";
permute(a, 0, 2);
getchar();
return 0;
}
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2. find the sum of contiguous subarray within a one-dimensional array of numbers which has the largest sum.
#include<stdio.h>
int maxSubArraySum(int a[], int size)
{
int max_so_far = 0, max_ending_here = 0;
int i;
for(i = 0; i < size; i++)
{
max_ending_here = max_ending_here + a[i];
if(max_ending_here < 0)
max_ending_here = 0;
if(max_so_far < max_ending_here)
max_so_far = max_ending_here;
}
return max_so_far;
}
int main()
{
int a[] = {-2, -3, 4, -1, -2, 1, 5, -3};
int max_sum = maxSubArraySum(a, 8);
printf("Maximum contiguous sum is %d\n", max_sum);
getchar();
return 0;
}
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posted on 2012-07-05 17:51
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