Create 01 - Recursive Approach (caused TLE).cpp

Author: JawadSher

24 - Dynamic Programming Problems/35 - Best Time To Buy and Sell Stock with Transaction Fee/01 - Recursive Approach (caused TLE).cpp

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+class Solution {
+public:
+    // Helper function to calculate the maximum profit
+    int solve(vector<int>& prices, int index, int buy, int fee) {
+        int n = prices.size(); // Get the size of the prices array
+
+        // Base case: If we've reached the end of the array, no more transactions can be made
+        if(index == n) return 0;
+
+        int profit = 0;
+
+        // If we are in a buying state (buy == 1), we can either:
+        // 1. Buy the stock at current price (this is represented by -prices[index])
+        //    and move to the next index (index+1) in a "sell" state (buy = 0).
+        // 2. Skip this index (do nothing) and stay in the "buy" state (buy = 1).
+        if(buy) {
+            profit = max((-prices[index] + solve(prices, index+1, 0, fee)), // Buy and move to the sell state
+                          (0 + solve(prices, index+1, 1, fee))); // Do nothing and stay in the buy state
+        } else {
+            // If we are in a selling state (buy == 0), we can either:
+            // 1. Sell the stock at current price (this is represented by +prices[index] - fee)
+            //    and move to the next index (index+1) in a "buy" state (buy = 1).
+            // 2. Skip this index (do nothing) and stay in the "sell" state (buy = 0).
+            profit = max((+prices[index] - fee + solve(prices, index+1, 1, fee)), // Sell and move to the buy state
+                          (0 + solve(prices, index+1, 0, fee))); // Do nothing and stay in the sell state
+        }
+
+        // Return the maximum profit for the current state
+        return profit;
+    }
+
+    // Main function to calculate the maximum profit with transaction fee
+    int maxProfit(vector<int>& prices, int fee) {
+        // Start solving from index 0 with the possibility of buying (buy = 1)
+        return solve(prices, 0, 1, fee);
+    }
+};