81_SearchinRotatedSortedArrayII - a920604a/leetcode GitHub Wiki
title: 81. Search in Rotated Sorted Array II
如果最左邊或最右邊與中間一樣(因為可能重複數值),就往將右索引往左移動一個
class Solution {
public:
bool search(vector<int>& nums, int target) {
int n = nums.size();
int l = 0, r = n-1;
while(l<=r){
int mid = l+ (r-l)/2;
if(nums[mid] == target) return true;
// 右半部遞增
else if(nums[mid] < nums[r]){
if(nums[mid] < target && target<= nums[r]) l = mid+1;
else r = mid-1;
}
else if(nums[mid] > nums[r]){
if(nums[l] <= target && target < nums[mid]) r = mid-1;
else l = mid+1;
}
else r--;
}
return false;
}
};
- time complexity
O(logn)
- space complexity
O(1)