HDU 1257 最少拦截系统

简单dp

#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
using namespace std;

const int maxn=1000;
int a[maxn];
int b[maxn];
int n;
int ans;


int main()
{
    while(~scanf("%d",&n)){
    for(int i=1;i<=n;i++) scanf("%d",&a[i]);
    ans=1;
    for(int i=1;i<=n;i++) b[i]=99999;

    for(int i=1;i<=n;i++)
    {
        int pos=ans+1;
        int tmp;
        for(int j=1;j<=ans;j++)
        {
            if(b[j]>=a[i])
            {
                if(pos==ans+1)
                {
                    pos=j;
                    tmp=b[j];

                }
                else
                {
                    if(b[j]<tmp)
                    {
                        tmp=b[j];
                        pos=j;
                    }
                }
            }
        }
        if(pos==ans+1) ans++;
        b[pos]=a[i];
    }
    printf("%d
",ans);
    }
    return 0;
}