543A.cpp

#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
using namespace std;
#define DEBUG(x) cout << '>' << #x << ':' << x << endl;
#define FOR0(i,n) for(int i=0, _##i=(n); i<_##i; ++i)
#define FOR(i,l,r) for(int i=(l), _##i=(r); i<_##i; ++i)
#define FORD(i,l,r) for(int i=(r), _##i=(l); --i>=_##i; )
#define repi(i,a) for(__typeof((a).begin()) i=(a).begin(), _##i=(a).end(); i!=_##i; ++i)
#define dwni(i,a) for(__typeof((a).rbegin()) i=(a).rbegin(), _##i=(a).rend(); i!=_##i; ++i)
#define SZ(a) ((int)((a).size()))
#define printCase() "Case #" << caseNum << ": "
#define pb push_back
#define mp make_pair
#define INF ((int)1e9)
#define SYNC std::ios::sync_with_stdio(false);  cin.tie(NULL);
#define ff first
#define ss second
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef vector<int> vi;
typedef vector<vi> vvi;
#define N 505
int main() {
    SYNC
    int n,m,b,mod,a[N],dp[2][N][N] = {};
    cin >> n >> m >> b >> mod;
    FOR0(i, n) cin >> a[i];
    dp[1][0][0] =  1;
    FOR0(i, n) {
        FOR(line,0,m+1) {
            FOR0(bugs,b+1) {
                int & cur = dp[i&1][line][bugs];
                cur = dp[!(i&1)][line][bugs];
                if(bugs >= a[i] && line > 0) cur = (cur + dp[(i&1)][line-1][bugs-a[i]]) % mod;
                cur = (cur + mod) % mod;
            }
        }
    }
    int ans = 0;
    FOR0(i, b + 1) ans = (ans + dp[(n-1)&1][m][i]) % mod;
    cout << (ans+mod) % mod << endl;
}