CF 605A(Sorting Railway Cars-贪心)

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给一个序列为1~n的一个排列，每次从序列中任意取一个数扔到开头或末尾，求使数列有序的最小操作次数。

一开始以为LIS，实际不是
要求 the longest subsegment of pos, where pos[a], pos[a+1], …, pos[b] is increasing.

#include<cstdio>#include<cstring>#include<cstdlib>#include<algorithm>#include<functional>#include<iostream>#include<cmath>#include<cctype>#include<ctime>using namespace std;#define For(i,n) for(int i=1;i<=n;i++)#define Fork(i,k,n) for(int i=k;i<=n;i++)#define Rep(i,n) for(int i=0;i<n;i++)#define ForD(i,n) for(int i=n;i;i--)#define RepD(i,n) for(int i=n;i>=0;i--)#define Forp(x) for(int p=pre[x];p;p=next[p])#define Forpiter(x) for(int &p=iter[x];p;p=next[p])  #define Lson (x<<1)#define Rson ((x<<1)+1)#define MEM(a) memset(a,0,sizeof(a));#define MEMI(a) memset(a,127,sizeof(a));#define MEMi(a) memset(a,128,sizeof(a));#define INF (2139062143)#define F (100000007)typedef long long ll;ll mul(ll a,ll b){return (a*b)%F;}ll add(ll a,ll b){return (a+b)%F;}ll sub(ll a,ll b){return (a-b+llabs(a-b)/F*F+F)%F;}void upd(ll &a,ll b){a=(a%F+b%F)%F;}int n;int h[1000000]={0};void find(){    MEMI(h)    For(i,n) {        int p;        scanf("%d",&p);         h[p]=i;    }    int len=1,ans=1;    Fork(i,2,n)    {        if (h[i]>h[i-1]) ans=max(ans,++len);        else len=1;    }    cout<<n-ans<<endl;}int main(){//  freopen("C.in","r",stdin);//  freopen(".out","w",stdout);    cin>>n;    find();    return 0;}

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