why pls

#include <bits/stdc++.h>

using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n, k, a, b;
    cin >> n >> k >> a >> b;
    vector<int> s(n);
    for(int i = 0; i < n; ++i){
        cin >> s[i];
    }
    vector<vector<int>> dp(n, vector<int> (k, 1e9));
    for(int i = a; i <= b; ++i){
        dp[i][0] = s[i] - s[0];
    }
    for(int i = a; i < n; ++i){
        for(int j = 1; j < k; ++j){
            for(int v = a; v <= b; ++v){
                if(i - a > 0)dp[i][j] = min(dp[i - v][j - 1] + s[i] - s[i - v + 1], dp[i][j]);
            }
        }
    }
    for(int i = 0; i < n; ++i){
        for(int j = 0; j < k; ++j){
            cout << dp[i][j] << " ";
        }
        cout << endl;
    }
    cout << endl;
}