BZOJ4990&&BZOJ4993(Usaco2017 Feb)[Why Did the Cow Cross the Road II]--最长升

【链接】
bzoj4990
bzoj4993

【解题报告】

最长公共子序列转最长升。

#include<cstdio>#include<cstring>#include<algorithm>using namespace std;const int maxn=1000005;int n,m,ans,a[maxn],que[maxn];int Abs(int x) {if (x<0) return (-x); return x;}int Find(int x){    int L=1,R=n;    while (L<=R)    {        int mid=(R-L>>1)+L;        if (x>que[mid]) L=mid+1; else R=mid-1;    }    return R;}int main(){    freopen("4990.in","r",stdin);    freopen("4990.out","w",stdout);    scanf("%d",&n); m=ans=0;    for (int i=1,x; i<=n; i++) scanf("%d",&x),a[x]=i;    memset(que,63,sizeof(que));    for (int i=1; i<=n; i++)    {        int x,c[10],cnt=0; scanf("%d",&x);        for (int k=-4; k<=4; k++)         if (x+k>=1&&x+k<=n) c[++cnt]=a[x+k];        sort(c+1,c+1+cnt);        for (int j=cnt; j; j--)        {            x=Find(c[j]);            que[x+1]=c[j];            if (x+1>ans) ans=x+1;        }    }    printf("%d",ans);    return 0;}