Follow up for "Search in Rotated Sorted Array":
What if duplicates are allowed?
Would this affect the run-time complexity? How and why?
Write a function to determine if a given target is in the array.
1 class Solution { 2 public: 3 int findPos(int a[], int left, int right) 4 { 5 if (left > right) 6 return -1; 7 8 int mid = left + (right - left) / 2; 9 10 if (a[left] < a[mid]) 11 { 12 int pos = findPos(a, mid + 1, right); 13 if (pos == -1) 14 return left; 15 else 16 return a[pos] <= a[left] ? pos : left; 17 } 18 else if (a[left] > a[mid]) 19 { 20 int pos = findPos(a, left, mid - 1); 21 if (pos == -1) 22 return mid; 23 else 24 return a[pos] < a[mid] ? pos : mid; 25 } 26 else 27 { 28 int pos1 = findPos(a, left, mid - 1); 29 int pos2 = findPos(a, mid + 1, right); 30 if (pos1 == -1 && pos2 == -1) 31 return mid; 32 else if (pos1 == -1) 33 return a[mid] < a[pos2] ? mid : pos2; 34 else if (pos2 == -1) 35 return a[mid] <= a[pos1] ? mid : pos1; 36 else 37 { 38 if (a[pos1] < a[pos2]) 39 return a[mid] <= a[pos1] ? mid : pos1; 40 else 41 return a[mid] < a[pos2] ? mid : pos2; 42 } 43 } 44 } 45 46 bool bsearch(int a[], int left, int right, int key) 47 { 48 if (left > right) 49 return false; 50 51 int mid = left + (right - left) / 2; 52 53 if (a[mid] == key) 54 return true; 55 else if (a[mid] < key) 56 return bsearch(a, mid + 1, right, key); 57 else 58 return bsearch(a, left, mid - 1, key); 59 } 60 61 bool search(int A[], int n, int target) { 62 // Start typing your C/C++ solution below 63 // DO NOT write int main() function 64 int pos = findPos(A, 0, n - 1); 65 return bsearch(A, 0, pos - 1, target) || bsearch(A, pos, n - 1, target); 66 } 67 };