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.
# include <stdio.h> /* Function to swap values at two pointers */ void swap ( char *x, char *y) { char temp; temp = *x; *x = *y; *y = temp; } /* Function to print permutations of string This function takes three parameters: 1. String 2. Starting index of the string 3. Ending index of the string. */ 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)); //backtrack } } } /* Driver program to test above functions */ int main() { char a[] = "ABC" ; permute(a, 0, 2); getchar (); return 0; } |
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; } /*Driver program to test maxSubArraySum*/ 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; } |