Create 713-Subarray-Product-Less-Than-K.java

Author: SharmaTushar1

java/713-Subarray-Product-Less-Than-K.java

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+//Solution taken from Leetcode's solution section
+//The answer is simple the only tricky thing is the ans+=right-left+1; because of which I got stuck
+//Here's an amazing explanation for that | taken form https://leetcode.com/problems/subarray-product-less-than-k/solution/348324
+//Say, if we have an array nums = [10,5,2,6] and k = 100
+//At first, we have window with 10 so ans = 0+1 and product will be 10
+//After that we will move the window since product<k so ans+=right-left+1 tells us the total number of possible outcomes
+//How?? See we have 5 as the new value. So, the new possible subarrays are [5] and [10,5] which is right-left+1 (1-0+1 == 2)
+//Similarly you can see this pattern further (try it yourself or see the linked comment for more details)
+class Solution {
+    public int numSubarrayProductLessThanK(int[] nums, int k) {
+        if (k<=1) return 0;
+        int left = 0;
+        int product = 1;
+        int ans = 0;
+        for (int right = 0; right<nums.length; right++) {
+            product *= nums[right];
+            while (product>=k) product/=nums[left++];
+            ans += right-left+1;
+        }
+        return ans;
+    }
+}