1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
#include <bits/stdc++.h>
using namespace std;

int a[1010];
int wyn = 0;
int n, k; 

inline void fix(int i, int j){
	int diff = a[i] - a[j];
	if (diff > k) {
		a[j] += diff - k;
		wyn += diff - k;
	}
}

int main() {
	ios_base::sync_with_stdio(0);
	cin >> n >> k;
	
	for (int i = 0; i < n; i++) cin >> a[i];
	
	for (int p = 1; p <= 1050; p++) {
		for (int i = 1; i < n; i++) {
			fix(i, i-1);
			fix(i-1, i);
		}
	}
	
	cout << wyn << endl;
	
	return 0;
}