-
Notifications
You must be signed in to change notification settings - Fork 10
/
NKTREE.cpp
51 lines (43 loc) 路 949 Bytes
/
NKTREE.cpp
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
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> ii;
typedef unsigned long long ull;
#define X first
#define Y second
#define pb push_back
#define mp make_pair
#define ep emplace_back
#define EL printf("\n")
#define sz(A) (int) A.size()
#define FOR(i,l,r) for (int i=l;i<=r;i++)
#define FOD(i,r,l) for (int i=r;i>=l;i--)
#define fillchar(a,x) memset(a, x, sizeof (a))
#define faster ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
int a[55000],n,x,y,z;
int main() {
// freopen("INP.TXT", "r", stdin);
// freopen("OUT.TXT", "w", stdout);
while (scanf("%d",&x) == 1) {
n++;
a[n] = x;
}
for (int i=1; i<=n-2; i++) {
x = a[i];
y = a[i+1];
z = a[i+2];
if (y < x) {
if (z < y) continue;
if (z < x) continue;
printf("NO");
return 0;
} else {
if (y < z) continue;
if (x < z) continue;
printf("NO");
return 0;
}
}
printf("YES");
return 0;
}