程序代码：

#include <cstdio>
#include <algorithm>

using namespace std;

const int INF = 1000000000;
const int MAX_N = 20;

int dp[MAX_N][MAX_N];
int a[MAX_N], b[MAX_N], c[MAX_N];

int main() {
    int n;
    while (scanf("%d", &n), n) {
    int h, s, f;
    scanf("%d%d%d", &h, &s, &f);
    for (int i = 1; i <= n; ++i) {
        scanf("%d", a + i);
        b[i] = a[i];
    }
    sort(b + 1, b + n + 1);
    int maxi = 0;
    for (int i = 1; i <= n; ++i) {
        c[i] = lower_bound(b + 1, b + n + 1, a[i]) - b;
        maxi = max(maxi, c[i]);
    }
    for (int i = 0; i <= n; ++i)
        for (int j = 0; j <= maxi; ++j)
        dp[i][j] = INF;
    dp[0][0] = 0;
    for (int i = 1; i <= n; ++i) {
        for (int j = 1; j <= maxi; ++j) {
        if (a[j] < a[i]) continue;
        for (int k = 1; k <= maxi; ++k) {
            int w;
            if (a[j] < a[k]) w = (a[k] - a[j]) * f;
            else if (a[j] == a[k]) w = 0;
            else w = (a[j] - a[k]) * h;
            w += a[j] * s;
            dp[i][j] = min(dp[i][j], dp[i - 1][k] + w);
        }
        }
    }
    int ret = INF;
    for (int j = c[n]; j <= maxi; ++j)
        ret = min(ret, dp[n][j]);
    printf("%d\n", ret);
    }
    return 0;
}