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[LeetCode 152] Maximum Product Subarray
Problem
Given an integer array nums, find a contiguous non-empty subarray within the array that has the largest product, and return the product.
The test cases are generated so that the answer will fit in a 32-bit integer.
A subarray is a contiguous subsequence of the array.
Example 1:
Input: nums = [2,3,-2,4]
Output: 6
Explanation: [2,3] has the largest product 6.
Example 2:
Input: nums = [-2,0,-1]
Output: 0
Explanation: The result cannot be 2, because [-2,-1] is not a subarray.
Constraints:
1 <= nums.length <= 2 * 10^4-10 <= nums[i] <= 10- The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit integer.
Thoughts
- We can store current min & max
- Reset current min & max when we have 0
TypeScript
function maxProduct(nums: number[]): number {
// set default value
let res: number = Math.max(...nums);
let curMin: number = 1, curMax: number = 1;
for(let num of nums){
if(num === 0){
curMin = 1
curMax = 1
continue;
}
const temp: number = num*curMax;
curMax = Math.max(num*curMax, num*curMin, num);
curMin = Math.min(temp, num*curMin, num)
res = Math.max(res, curMax)
}
return res;
};