Problem
Given an integer array, find three numbers whose product is maximum and output the maximum product.
Example 1:
Input: [1,2,3]
Output: 6
Example 2:
Input: [1,2,3,4]
Output: 24
Note:
The length of the given array will be in range [3,10^4] and all elements are in the range [-1000, 1000].
Multiplication of any three numbers in the input won't exceed the range of 32-bit signed integer.
Solution
follow-up: max product of k numbers
class Solution {
public int maximumProduct(int[] nums) {
int len = nums.length;
if (len < 3) return 0;
Arrays.sort(nums);
if (nums[0]*nums[len-1] >= 0) {
return nums[len-1]*nums[len-2]*nums[len-3];
}
int l = 0, r = len-1, res = 1, count = 3;
while (count > 0) {
if (count%2 == 1) {
res *= nums[r];
r -= 1;
count -= 1;
}
else {
if (nums[r]*nums[r-1] > nums[l]*nums[l+1]) {
res *= nums[r]*nums[r-1];
r -= 2;
} else {
res *= nums[l]*nums[l+1];
l += 2;
}
count -= 2;
}
}
return res;
}
}
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