Merge pull request #1057 from osama-swe/main

Added my sol to 6 May

05- May/06- Number of Subsequences That Satisfy the Given Sum Condition/06- Number of Subsequences That Satisfy the Given Sum Condition (Osama Ayman).java

@@ -0,0 +1,32 @@
+// Author: Osama Ayman
+// Time: O(nlogn)
+// Space: O(n)
+class Solution {
+
+    public int numSubseq(int[] nums, int target) {
+        int mod = (int) 1e9+7;
+        // Sort the array and apply the 2-pointers strategy
+        Arrays.sort(nums);
+        int n = nums.length;
+        // Precompute the value of 2 to the power of each value.
+        int[] power = new int[n];
+        power[0] = 1;
+        for (int i = 1; i < n; ++i) {
+            power[i] = (power[i - 1] * 2) % mod;
+        }
+
+        int left = 0;
+        int right = nums.length-1;
+        int res = 0;
+        while(left <= right){
+            if(nums[left] + nums[right] <= target){
+                // the number of subsequences is 2 ^ (right-left)
+                res += power[right - left];
+                res %= mod;
+                left++;
+            }
+            else right--;
+        }
+        return res;
+    }
+}