HDU - 1025 -最长上升子序列nlogn

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1025

刚开始题目理解错了，第一个数字是a数组下标，第二个是数组的值，nlogn算法写法用到了二分查找

还有这题输出很坑，一个道路是是road，两个以上是roads

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<math.h>
#include<set>
#include<vector>
#include<sstream>
#include<queue>
#define ll long long
#define PI 3.1415926535897932384626
#define inf 0x3f3f3f3f
using namespace std;
const int maxn=500010;
int a[maxn],b[maxn];
int Search(int num,int low,int high)
{
    int mid;
    while(low<=high){
        mid=(low+high)/2;
        if(num>=b[mid])low=mid+1;
        else high=mid-1;
    }
    return low;
}
int dp(int n)
{
    int i,len,pos;
    b[1]=a[1];
    len=1;
    for(i=2;i<=n;i++){
        if(a[i]>=b[len]){
            len=len+1;
            b[len]=a[i];
        }
        else
        {
            pos=Search(a[i],1,len);
            b[pos]=a[i];
        }
    }
    return len;
}
int main()
{
    int n,k=1;;
    while(scanf("%d",&n)!=EOF){
        int x,y;
        for(int i=1;i<=n;i++){
        scanf("%d%d",&x,&y);
        a[x]=y;
        }
        int ans=dp(n);
        printf("Case %d:\n",k++);
        if(ans==1)
        printf("My king, at most %d road can be built.\n\n",ans);
        else
        printf("My king, at most %d roads can be built.\n\n",ans);
    }
        return 0;
}