CodeForces 599C Day at the Beach（RMQ）

题意：给你n个数，问你最多分成多少块，使得在块内单独排序之后，然后再组合起来的结果和最后排序的结果一样

思路：扫一遍，如果这个块的最大值比下一个块的最小值小的话那么就ans++，用个RMQ就可以了

#include<bits\stdc++.h>
using namespace std;
const int maxn = 1e5+6;
int rmq[maxn][20];
int a[maxn],n;
void init()
{
	for (int i = 0;i<n;i++)
		rmq[i][0]=a[i];
	for (int j = 1;(1<<j)<=n;j++)
		for (int i = 0;i+(1<<j)<=n;i++)
			rmq[i][j]=min(rmq[i][j-1], rmq[i+(1<<(j-1))][j-1]);
}
int RMQ(int L,int R)
{
	int k = 0;
	while((1<<(k+1))<=R-L+1)
		k++;
	return min(rmq[L][k],rmq[R-(1<<k)+1][k]);
}

int main()
{
	scanf("%d",&n);
	for (int i = 0;i<n;i++)
		scanf("%d",&a[i]);
	int Max = a[0],ans=0;
	init();
	for (int i = 1;i<n;i++)
	{
		if(Max<=RMQ(i,n-1))
			ans++;
		Max = max(Max,a[i]);
	}
	printf("%d\n",ans+1);
}

Description

One day Squidward, Spongebob and Patrick decided to go to the beach. Unfortunately, the weather was bad, so the friends were unable to ride waves. However, they decided to spent their time building sand castles.

At the end of the day there were n castles built by friends. Castles are numbered from 1 to n, and the height of the i-th castle is equal toh_i. When friends were about to leave, Squidward noticed, that castles are not ordered by their height, and this looks ugly. Now friends are going to reorder the castles in a way to obtain that condition h_i ≤ h_i + 1 holds for all i from 1 to n - 1.

Squidward suggested the following process of sorting castles:

• Castles are split into blocks — groups of consecutive castles. Therefore the block from i to j will include castles i, i + 1, ..., j. A block may consist of a single castle.
• The partitioning is chosen in such a way that every castle is a part of exactly one block.
• Each block is sorted independently from other blocks, that is the sequence h_i, h_i + 1, ..., h_j becomes sorted.
• The partitioning should satisfy the condition that after each block is sorted, the sequence h_i becomes sorted too. This may always be achieved by saying that the whole sequence is a single block.

Even Patrick understands that increasing the number of blocks in partitioning will ease the sorting process. Now friends ask you to count the maximum possible number of blocks in a partitioning that satisfies all the above requirements.

Input

The first line of the input contains a single integer n (1 ≤ n ≤ 100 000) — the number of castles Spongebob, Patrick and Squidward made from sand during the day.

The next line contains n integers h_i (1 ≤ h_i ≤ 10⁹). The i-th of these integers corresponds to the height of the i-th castle.

Output

Print the maximum possible number of blocks in a valid partitioning.

Sample Input

Input

3
1 2 3

Output

3

Input

4
2 1 3 2

Output

2

Hint

In the first sample the partitioning looks like that: [1][2][3].

In the second sample the partitioning is: [2, 1][3, 2]