[HDU] 1025 Constructing Roads In JGShining's Kingdom - 二分的求最大递增非连续子序列

#include<iostream>
#include<math.h>
#include<algorithm>
#include<stack>
using namespace std;
int const MAX =0x3f3f3f3f;
struct Road
{
int p;
int r;
};
bool cmp(Road x,Road y)
{
if(x.p < y.p )
return true;
return false;
}
Road roads[500001];
int counts[500001];
int main()
{
int n=0,tc=1;
while(scanf("%d",&n)!=EOF)
{
memset(counts,0,sizeof(counts));
for(int i=0;i<n;i++)
scanf("%d %d",&roads[i].p,&roads[i].r);
sort(roads,roads+n,cmp);
counts[1] = roads[0].r;
counts[0] = 0;
int len=1;
for(int i=1;i<n;i++)
{
int p = 0,ed = len,mid;
while(p<=ed)
{
mid = (p+ed)/2;
if(counts[mid]>=roads[i].r)
ed = mid-1;
else
p=mid+1;
}
counts[p]=roads[i].r;
if(p>len)len++;
}
cout<<"Case "<<tc<<":"<<endl;
if(len>1)
cout<<"My king, at most "<<len<<" roads can be built."<<endl;
else
cout<<"My king, at most "<<len<<" road can be built."<<endl;
cout<<endl;
tc++;
}
return 0;
}