Memoize

#include <bits/stdc++.h>
#define INF 1e9

using namespace std;

long long memo[300001] = {0};

long long solve(int n, int a, int b){
    // compute and return answer here
    if(n == 0)
        return a;
    if(n == 1)
        return b;
    long long ans = INF;
    if(memo[n] == 0)
    {
        ans = min(a + solve(n - 1, a, b), b + solve(n - 2, a, b));
        memo[n] = ans;
    }

    return memo[n];
}

int main() {
    int q, a, b, n;
    cin >> q >> a >> b;
    for(int i = 0; i < q; i++){
          // use scanf/printf to prevent TLE
        scanf("%d",&n);
        printf("%d\n",solve(n,a,b));
    }
}