Create 01 - Recursive Approach (caused TLE).cpp

Author: JawadSher

24 - Dynamic Programming Problems/25 - Minimum Swaps To Make Sequences Increasing/01 - Recursive Approach (caused TLE).cpp

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+class Solution {
+public:
+    // Recursive helper function to solve the problem
+    // `nums1` and `nums2` are the input arrays
+    // `index` represents the current position in the arrays
+    // `n` is the size of the arrays
+    // `swapped` indicates if the previous elements were swapped
+    int solve(vector<int>& nums1, vector<int>& nums2, int index, int n, bool swapped) {
+        // Base case: if we reach the end of the arrays, no swaps are needed
+        if (index >= n) return 0;
+
+        // Initialize the minimum swaps required as a large value
+        int ans = INT_MAX;
+
+        // Retrieve the previous elements in both arrays
+        int prev1 = nums1[index - 1];
+        int prev2 = nums2[index - 1];
+
+        // If the previous elements were swapped, reverse them
+        if (swapped) swap(prev1, prev2);
+
+        // Case 1: No swap at the current index
+        // Check if the current elements maintain the increasing order without a swap
+        if (nums1[index] > prev1 && nums2[index] > prev2)
+            ans = solve(nums1, nums2, index + 1, n, 0);
+
+        // Case 2: Swap at the current index
+        // Check if swapping the current elements maintains the increasing order
+        if (nums1[index] > prev2 && nums2[index] > prev1)
+            ans = min(ans, 1 + solve(nums1, nums2, index + 1, n, 1));
+
+        // Return the minimum number of swaps required
+        return ans;
+    }
+
+    // Main function to find the minimum number of swaps needed
+    int minSwap(vector<int>& nums1, vector<int>& nums2) {
+        // Insert dummy values at the start of both arrays to simplify comparisons
+        nums1.insert(nums1.begin(), -1);
+        nums2.insert(nums2.begin(), -1);
+
+        // Get the size of the arrays
+        int n = nums1.size();
+
+        // Initialize the swapped flag as false
+        bool swapped = 0;
+
+        // Start solving from the first actual element
+        return solve(nums1, nums2, 1, n, swapped);
+    }
+};