标签：time medium exists code tag hal highlight cat class
Suppose a sorted array is rotated at some pivot unknown to you beforehand. (i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2). You are given a target value to search. If found in the array return its index, otherwise return -1. You may assume no duplicate exists in the array. Have you met this question in a real interview? Yes Example For [4, 5, 1, 2, 3] and target=1, return 2. For [4, 5, 1, 2, 3] and target=0, return -1. Challenge O(logN) time Tags Sorted Array Array LinkedIn Binary Search Uber Facebook Related Problems Medium Search in Rotated Sorted Array II 40 % Easy Search a 2D Matrix
有序数组的题, 二分法, 根据mid的位置再确定start 和end的位置, 画图分情况
public int search(int[] A, int target) {
// write your code here
if (/*A == null ||*/ A.length == 0){
return -1;
}
int start = 0, end = A.length - 1;
while (start + 1 < end) {
int mid = start + (end - start) / 2;
if (A[mid] == target) {
return mid;
}
if (A[start] < A[mid] && A[start] > A[end]){
if (A[mid] > target && A[start] <= target) {
end = mid;
} else {
start = mid;
}
} else if (A[start] <= A[mid] && A[mid] <= A[end]) {
if (A[mid] < target) {
start = mid;
} else {
end = mid;
}
} else {
if (A[mid] < target && target <= A[end]) {
start = mid;
} else {
end = mid;
}
}
}
if (A[start] == target) {
return start;
} else if (A[end] == target) {
return end;
} else {
return -1;
}
}
Search in Rotated Sorted Array
标签：time medium exists code tag hal highlight cat class
原文地址：http://www.cnblogs.com/apanda009/p/7262292.html
