Two-Hundred-Forty-Nine Commit: Add Subarray Sums Divisible by K problem to Prefix Sum Section

Author: AAdewunmi

src/_0_1_Knapsack_Dynamic_Programming/0_1_Knapsack_Dynamic_Programming.txt renamed to src/Dynamic_Programming/_0_1_Knapsack_Dynamic_Programming/0_1_Knapsack_Dynamic_Programming.txt

@@ -1,4 +1,4 @@
-package _0_1_Knapsack_Dynamic_Programming;
+package Dynamic_Programming._0_1_Knapsack_Dynamic_Programming;
 
 // Problem Statement: 0/1 Knapsack (medium)
 // LeetCode Question:

src/_0_1_Knapsack_Dynamic_Programming/Problem_1_0_1_Knapsack.java renamed to src/Dynamic_Programming/_0_1_Knapsack_Dynamic_Programming/Problem_1_0_1_Knapsack.java

@@ -1,4 +1,4 @@
-package _0_1_Knapsack_Dynamic_Programming;
+package Dynamic_Programming._0_1_Knapsack_Dynamic_Programming;
 
 // Problem Statement: Equal Subset Sum Partition (medium)
 // LeetCode Question: 416. Partition Equal Subset Sum

src/_0_1_Knapsack_Dynamic_Programming/Problem_2_Equal_Sum_Partition.java renamed to src/Dynamic_Programming/_0_1_Knapsack_Dynamic_Programming/Problem_2_Equal_Sum_Partition.java

@@ -1,4 +1,4 @@
-package _0_1_Knapsack_Dynamic_Programming;
+package Dynamic_Programming._0_1_Knapsack_Dynamic_Programming;
 
 // Problem Statement: Subset Sum (medium)
 // LeetCode Question:

src/_0_1_Knapsack_Dynamic_Programming/Problem_3_Equal_Subset_Sum_Partition.java renamed to src/Dynamic_Programming/_0_1_Knapsack_Dynamic_Programming/Problem_3_Equal_Subset_Sum_Partition.java

@@ -1,4 +1,4 @@
-package _0_1_Knapsack_Dynamic_Programming;
+package Dynamic_Programming._0_1_Knapsack_Dynamic_Programming;
 
 // Problem Statement: Minimum Subset Sum Difference (hard)
 // LeetCode Question: 2035. Partition Array Into Two Arrays to Minimize Sum Difference

src/_0_1_Knapsack_Dynamic_Programming/Problem_4_Minimum_Subset_Sum_Difference.java renamed to src/Dynamic_Programming/_0_1_Knapsack_Dynamic_Programming/Problem_4_Minimum_Subset_Sum_Difference.java

@@ -1,4 +1,4 @@
-package _0_1_Knapsack_Dynamic_Programming;
+package Dynamic_Programming._0_1_Knapsack_Dynamic_Programming;
 
 // Problem Statement: Count of Subset Sum (hard)
 // LeetCode Question:

src/_0_1_Knapsack_Dynamic_Programming/Problem_5_Count_Of_Subset_Sum.java renamed to src/Dynamic_Programming/_0_1_Knapsack_Dynamic_Programming/Problem_5_Count_Of_Subset_Sum.java

@@ -1,4 +1,4 @@
-package _0_1_Knapsack_Dynamic_Programming;
+package Dynamic_Programming._0_1_Knapsack_Dynamic_Programming;
 
 // Problem Statement: Target Sum (hard)
 // LeetCode Question: 494. Target Sum

src/_0_1_Knapsack_Dynamic_Programming/Problem_6_Target_Sum.java renamed to src/Dynamic_Programming/_0_1_Knapsack_Dynamic_Programming/Problem_6_Target_Sum.java

@@ -0,0 +1,25 @@
+package Prefix_Sum;
+
+// Problem Statement: Subarray Sums Divisible by K
+// LeetCode Question: 974. Subarray Sums Divisible by K
+
+import java.util.HashMap;
+
+public class Problem_5_SubArray_Sums_Divisible_By_K {
+    public int subarraysDivByK(int[] nums, int k) {
+
+        HashMap<Integer, Integer> remainderCount = new HashMap<>();
+        remainderCount.put(0, 1);
+        int cumulativeSum = 0, count = 0;
+        
+        for (int num : nums) {
+            cumulativeSum += num;
+            int remainder = cumulativeSum % k;
+            if (remainder < 0) remainder += k;
+            count += remainderCount.getOrDefault(remainder, 0);
+            remainderCount.put(remainder, remainderCount.getOrDefault(remainder, 0) + 1);
+        }
+
+        return count;
+    }
+}