HDU 1257 ( 最少拦截系统 ) 最长单调子序列 二分+dp

1257 ( 最少拦截系统 )

#include<stdio.h>
int n,a,s[30001],l,m,num,r;
intmain()
{

(scanf("%d",&m)!=EOF)
       {
         num=0;
         while(m--)
         {
                 scanf("%d",&a);
                 if(num==0)
                 {
                    s[1] = a; num++;
                 }   //开一个系统，初始化 
                 else
                 {
                         if(a>s[num]) {
                                num++;s[num] = a;
                         }   //重开一个系统 
                             else
                         {
                                l=1,r= num;
                                while(l<=r)  //二分搜索a在b[i]中的位置 
                                {
                                        int m= (l+r)/2;
                                        if(s[m]==a)break;
                                        if(s[m]<a) l= m+1;
                                        if(s[m]>a) r= m-1;
                                }
                                if(l>r)
                                s[l] = a;
                         }
                 }
         }
         printf("%d\n",num);
       }
       return0;      
}