Update tribonacci_using_DP.cpp

tribonacci_using_DP.cpp

@@ -1,36 +1,35 @@
 #include <iostream>
-#include <map>
+#include <vector>
 
-using namespace std;
+int tribonacci(int n) {
+    // Base cases
+    if (n == 0) return 0;
+    if (n == 1 || n == 2) return 1;
 
-class Tribo {
-public:
-    int calc(int n, map<int, int> &memo) {
-        if (memo.find(n) != memo.end()) {
-            return memo[n];
-        } else {
-            int sol = calc(n - 1, memo) + calc(n - 2, memo) + calc(n - 3, memo);
-            memo[n] = sol;
-            return sol;
-        }
-    }
+    // Create a vector to store the Tribonacci numbers
+    std::vector<int> dp(n + 1, 0);
+
+    // Initialize base cases
+    dp[0] = 0;
+    dp[1] = 1;
+    dp[2] = 1;
 
-    int tribonacci(int n) {
-        map<int, int> memo;
-        memo[0] = 0;
-        memo[1] = 1;
-        memo[2] = 1;
-
-        return calc(n, memo);
+    // Fill the dp vector using the Tribonacci formula
+    for (int i = 3; i <= n; ++i) {
+        dp[i] = dp[i - 1] + dp[i - 2] + dp[i - 3];
     }
-};
+
+    // Return the nth Tribonacci number
+    return dp[n];
+}
 
 int main() {
-    Tribo t;
     int n;
-    cout << "Enter a number: ";
-    cin >> n;
-    int result = t.tribonacci(n);
-    cout << "Tribonacci of " << n << " is: " << result << endl;
+    std::cout << "Enter the value of n: ";
+    std::cin >> n;
+
+    int result = tribonacci(n);
+    std::cout << "The " << n << "th Tribonacci number is: " << result << std::endl;
+
     return 0;
 }