fibonacci

#include <iostream>
#include <vector>
using namespace std;

int fibonacci(int n) {
    if (n <= 1) return n;

    vector<int> dp(n + 1);
    dp[0] = 0;
    dp[1] = 1;

    for (int i = 2; i <= n; i++) {
        dp[i] = dp[i-1] + dp[i-2];
    }
    return dp[n];
}

Calculates the nth fibonacci number. Uses classic memoization technique to avoid redundant calculations.