Codeforces Round #424 A（模拟）

#include<cstdio>
int n,a[100007];
int main(){
    scanf("%d",&n);
    for(int i=1;i<=n;++i)scanf("%d",a+i);
    int L=1,R=n;
    while(L<n&&a[L]<a[L+1])++L;
    while(R>1&&a[R]<a[R-1])--R;
    for(int i=L+1;i<=R;++i)if(a[L]!=a[i])return puts("NO"),0;
    return puts("YES"),0;
}

#include <iostream>
using namespace std;
int N;
int V[105];
int main()
{
    cin>>N;
    for(int i=1;i<=N;i++)cin>>V[i];
    int i=1;
    while(i<N&&V[i]<V[i+1])i++;
    while(i<N&&V[i]==V[i+1])i++;
    while(i<N&&V[i]>V[i+1])i++;
    if(i<N)cout<<"NO";
    else cout<<"YES";
    return 0;
}

#include<iostream>
#include<cstdio>
using namespace std;
int n;
int a[1001];
int main()
{
    scanf("%d",&n);
    for(int i=1;i<=n;i++)scanf("%d",a+i);
    int i=1;
    while(i+1<=n && a[i+1]>a[i])i++;
    while(i+1<=n && a[i+1]==a[i])i++;
    while(i+1<=n && a[i+1]<a[i])i++;
    if(i<n)printf("NO");else printf("YES");
    return 0;
} 

#include<bits/stdc++.h>
using namespace std;

int main()
{
    int n;
    cin>>n;
    int arr[n];
    for(int i=0;i<n;i++)
        cin>>arr[i];
    int i=0;
    while(arr[i+1]>arr[i] && i+1<n)
        i++;
    while(arr[i]==arr[i+1] && i+1<n)
        i++;
    while(arr[i]>arr[i+1] && i+1<n)
        i++;
    if(i==n-1)
        cout<<"YES";
    else cout<<"NO";


}

#include <bits/stdc++.h>

using namespace std;

int a[102];
int n;
void sol(string s) {
    cout << s;
    exit(0);
}
int main() {
#ifndef ONLINE_JUDGE
    freopen("CF.in", "r", stdin);
#endif
    cin >> n;
    for (int i = 1; i <= n; ++i)cin >> a[i];
    int i=1;
    while(i+1<=n&&a[i]<a[i+1])++i;
    while(i+1<=n&&a[i]==a[i+1])++i;
    while(i+1<=n)
    {
        if(a[i]<=a[i+1])sol("NO");
        ++i;
    }sol("YES");
}