# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
391074 | yu_lim | A Huge Tower (CEOI10_tower) | Java | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
import java.util.*;
import java.io.*;
public class HugeTower {
public static void main(String[] args) throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
StringTokenizer str = new StringTokenizer(br.readLine());
int N = Integer.parseInt(str.nextToken());
int D = Integer.parseInt(str.nextToken());
int M = 1_000_000_007;
int[] blocks = new int[N];
str = new StringTokenizer(br.readLine());
for (int i = 0; i < N; i++)
blocks[i] = Integer.parseInt(str.nextToken());
br.close();
Arrays.sort(blocks);
long[] towers = new long[N];
towers[0] = 1;
int prev = 0;
for (int i = 0; i < N; i++) {
while (prev < i) {
if (blocks[prev] + D < blocks[i])
prev++;
else
break;
}
// # of blocks <= i that can't stack on i
if (i > 0)
towers[i] = (((i - prev + 1) % M) * towers[i - 1]) % M;
}
System.out.println(towers[N - 1] % M);
}
}