[算法] 循环有序数组查找递归实现

#include<stdio.h>
#include<stdlib.h>

int main() {

int *array = (int *)malloc(sizeof(int)*16);
int i;
for(i = 0; i < 16; i++) {
*(array + i) = (i+5) % 16;
}

int ret = search(array, 16, 10);
printf("%d", ret);

return 0;
}

int isOrdered(int *array, int begin, int end) {
return *(array+end) > *(array+begin) ? 1 : 0;
}

int contains(int *array, int begin, int end, int theNum) {
return theNum >= *(array + begin) && theNum <= *(array + end) ? 1 : 0;
}

int CyclicOrderedBinarySearch(int *array, int begin, int end, int theNum) {
if(begin == end) {
if(*(array + begin) == theNum) {
return begin;
} else {
return -1;
}
}

int mid = (begin + end) / 2;
if(isOrdered(array, begin, mid)) {
if(contains(array, begin, mid, theNum)) {
return CyclicOrderedBinarySearch(array, begin, mid, theNum);
} else {
return CyclicOrderedBinarySearch(array, mid + 1, end, theNum);
}

} else {
if(contains(array, mid + 1, end, theNum)) {
return CyclicOrderedBinarySearch(array, mid + 1, end, theNum);
} else {
return CyclicOrderedBinarySearch(array, begin, mid, theNum);
}
}
return -1;
}

int search(int *array, int n, int theNum) {
return CyclicOrderedBinarySearch(array, 0, n - 1, theNum);
}