Given an integer array nums
, find the contiguous subarray within an array (containing at least one number) which has the largest product.
Example 1:
Input: [2,3,-2,4]
Output: 6
Explanation: [2,3] has the largest product 6.
Example 2:
Input: [-2,0,-1]
Output: 0
Explanation: The result cannot be 2, because [-2,-1] is not a subarray.
题解:
没想到O(n)算法,看讨论区是使用一个数存储当前最大一个存最小,遇到负数就交换最大最小。
class Solution {
public:
int maxProduct(vector<int>& nums) {
int n = nums.size();
if (n == 0) {
return 0;
}
int res = nums[0];
int maxi = nums[0], mini = nums[0];
for (int i = 1; i < n; i++) {
if (nums[i] < 0) {
int tmp = mini;
mini = maxi;
maxi = tmp;
}
maxi = max(maxi * nums[i], nums[i]);
mini = min(mini * nums[i], nums[i]);
res = max(maxi, res);
}
return res;
}
};