CF 258B. Sort the Array

http://codeforces.com/contest/451/problem/B做了这道题，会用reverse() 了，题目大意就是要得到一组上升的序列，需要将不规则的序列的子序列翻转。问能否经过翻转后得到一个上升的序列。B. Sort the Arraytime limit per test1 secondmemory limit per test256 megabytesinputstandard inputoutputstandard outputBeing a programmer, you like arrays a lot. For your birthday, your friends have given you an array a consisting of n distinct integers.Unfortunately, the size of a is too small. You want a bigger array! Your friends agree to give you a bigger array, but only if you are able to answer the following question correctly: is it possible to sort the array a (in increasing order) by reversing exactly one segment of a? See definitions of segment and reversing in the notes.InputThe first line of the input contains an integer n (1?≤?n?≤?105) — the size of array a.The second line contains n distinct space-separated integers: a[1],?a[2],?...,?a[n] (1?≤?a[i]?≤?109).OutputPrint "yes" or "no" (without quotes), depending on the answer.If your answer is "yes", then also print two space-separated integers denoting start and end (start must not be greater than end) indices of the segment to be reversed. If there are multiple ways of selecting these indices, print any of them.Sample test(s)input

3
3 2 1

output

yes
1 3

input

4
2 1 3 4

output

yes
1 2

input

4
3 1 2 4

output

no

input

2
1 2

output

yes
1 1

NoteSample 1. You can reverse the entire array to get [1,?2,?3], which is sorted.Sample 3. No segment can be reversed such that the array will be sorted.DefinitionsA segment [l,?r] of array a is the sequence a[l],?a[l?+?1],?...,?a[r].If you have an array a of size n and you reverse its segment [l,?r], the array will become:a[1],?a[2],?...,?a[l?-?2],?a[l?-?1],?a[r],?a[r?-?1],?...,?a[l?+?1],?a[l],?a[r?+?1],?a[r?+?2],?...,?a[n?-?1],?a[n].#include<iostream>
#include<cstring>
#include<algorithm>
#include<cstdlib>
#include<vector>
#include<cmath>
#include<stdlib.h>
#include<iomanip>
#include<list>
#include<deque>
#include<map>
#include <stdio.h>
#include <queue>

#define maxn 100000+5
#define ull unsigned long long
#define ll long long
#define reP(i,n) for(i=1;i<=n;i++)
#define rep(i,n) for(i=0;i<n;i++)
#define cle(a) memset(a,0,sizeof(a))
#define mod 90001
#define PI 3.141592657
#define INF 1<<30
const ull inf = 1LL << 61;
const double eps=1e-5;

using namespace std;

bool cmp(int a,int b){
return a>b;
}
int a[maxn];
int b[maxn];
int main()
{
//freopen("in.txt","r",stdin);
//freopen("out.txt","w",stdout);
int n;
cin>>n;
for(int i=0;i<n;i++)
{
cin>>a[i];
b[i]=a[i];
}
sort(b,b+n);
int x=-1,y;
for(int i=0;i<n;i++)
{
if(a[i]!=b[i]){x=i;break;}
}
if(x==-1){cout<<"yes"<<endl;cout<<1<<" "<<1<<endl;}
else
{
for(int i=n-1;i>=0;i--)
{
if(a[i]!=b[i]){y=i;break;}
}
reverse(a+x,a+y+1);
for(int i=0;i<n;i++)
if(a[i]!=b[i]){cout<<"no"<<endl;return 0;}
cout<<"yes"<<endl;cout<<x+1<<" "<<y+1<<endl;
}
return 0;
}