题目

//https://www.luogu.com.cn/problem/U152266
#include<bits/stdc++.h>
using namespace std;
int a[55][55][55], l, w, h, m, ans;
bool vis[55][55][55];
int dx[] = {0, 0, 0, 0, 1, -1};
int dy[] = {0, 0, 1, -1, 0, 0};
int dz[] = {1, -1, 0, 0, 0, 0};
struct node {
	int x, y, z;
	node() {}
	node(int i, int j, int k) {
		x = i, y = j, z = k;
	}
};
int _abs(int x) {
	return (x < 0) ? -x : x;
}
void bfs(int x, int y, int z) {
	queue<node> q;
	q.push(node(x, y, z));
	vis[x][y][z] = true;
	while (q.size()) {
		node t = q.front();
		q.pop();
		for (int i = 0; i < 6; i++) {
			int x1 = t.x + dx[i], y1 = t.y + dy[i], z1 = t.z + dz[i];
			if (x1 < 0 || y1 < 0 || z1 < 0 || x1 > l || y1 > w || z1 > h || vis[x1][y1][z1] || _abs(a[t.x][t.y][t.z] - a[x1][y1][z1]) > m)
				continue;
			q.push(node(x1, y1, z1));
			vis[x1][y1][z1] = true;
		}
	}
}
int main() {
	scanf("%d%d%d%d", &l, &w, &h, &m);
	for (int i = 1; i <= l; i++)
		for (int j = 1; j <= w; j++)
			for (int k = 1; k <= h; k++)
				scanf("%d", &a[i][j][k]);
	for (int i = 1; i <= l; i++)
		for (int j = 1; j <= w; j++)
			for (int k = 1; k <= h; k++)
				if (!vis[i][j][k]) {
					bfs(i, j, k);
					ans++;
				}
	printf("%d\n", ans);
	return 0;
}