# Sequential search analysis for a list with n items

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Sequential Search Analysis For a list with n items, the best case is when the value is equal to the first element of the list, in which case only one comparison is needed. The worst case is when the value is not in the list (or occurs only once at the end of the list), in which case n comparisons are needed.
Sequential - Pseudocode Forward iteration This Pseudocode describes a typical variant of linear search, where the result of the search is supposed to be either the location of the list item where the desired value was found; or an invalid location Λ, to indicate that the desired element does not occur in the list. For each item in the list: if that item has the desired value, stop the search and return the item's location. Return Λ .
Sequential Search - Pseudocode In this pseudocode, the last line is executed only after all list items have been examined with none matching. If the list is stored as an array data structure, the location may be the index of the item found (usually between 1 and n, or 0 and n−1). In that case the invalid location Λ can be any index before the first element (such as 0 or −1, respectively) or after the last one (n+1 or n, respectively). If the list is a simply linked list, then the item's location is its reference, and Λ is usually the null pointer.
Algorithm – Sequential Search
Analysis – Sequential Search
Analysis – Sequential Search
Sequential Search Program int binarySearch (int list[], int size, int key) { int first = 0, last , mid, position = -1; last = size - 1 int found = 0; while (!found && first <= last) { middle = (first + last) / 2; /* Calculate mid point */ if (list[mid] == key) { /* If value is found at mid */ found = 1; position = mid; } else if (list[mid] > key) /* If value is in lower half */ last = mid - 1; else first = mid + 1; /* If value is in upper half */ } // end while loop return position; } // end of function
Sequential Search
Brute-Force String Matching Given a string of n

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