Create 01 - Recursive Approach (caused TLE).cpp

Author: JawadSher

24 - Dynamic Programming Problems/24 - Partition Equal Subset Sum/01 - Recursive Approach (caused TLE).cpp

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+class Solution {
+public:
+    // Recursive helper function to check if we can partition the array into two subsets
+    int solve(vector<int>& nums, int index, int n, int target) {
+        // Base case: If the index exceeds the array size, return 0 (no valid partition)
+        if(index >= n) return 0;
+        
+        // If the target becomes negative, return 0 (not possible to partition)
+        if(target < 0) return 0;
+        
+        // If the target becomes zero, it means we've found a valid partition (return 1)
+        if(target == 0) return 1;
+
+        // Option 1: Include the current element and try to partition with the reduced target
+        int include = solve(nums, index+1, n, target - nums[index]);
+        
+        // Option 2: Exclude the current element and try to partition without changing the target
+        int exclude = solve(nums, index+1, n, target - 0);
+
+        // Return true if either including or excluding the current element leads to a valid partition
+        return include or exclude;
+    }
+
+    // Main function to check if we can partition the array into two subsets with equal sum
+    bool canPartition(vector<int>& nums) {
+        int total = 0;
+
+        // Calculate the total sum of the elements in the array
+        for(auto & num : nums) total += num;
+
+        // If the total sum is odd, we cannot partition it into two equal subsets
+        if(total & 1) return 0;
+
+        // Set the target as half of the total sum
+        int target = total / 2;
+
+        // Call the solve function to check if we can find a subset that sums to 'target'
+        return solve(nums, 0, nums.size(), target);
+    }
+};