C题 最长上升子序列（二分优化）

#include<iostream>using namespace std;#include<cstdio>int num[500011];int ans[500011];int main(){int n,k=1;int len,low,up,mid;int i;int temp1,temp2;while(scanf("%d",&n)!=-1){for(i=0;i<n;i++){scanf("%d%d",&temp1,&temp2);num[temp1]=temp2;}/*for(i=1;i<=temp1;i++)   cout<<num[i];        cout<<endl;*/ans[1]=num[1];len=1;for(i=2;i<=n;i++){/*****/                   //这个二分是别人写的，表示比我写的好多了- -I。low=1;up=len;while(low<=up){mid=(low+up)/2;if(ans[mid]<num[i]) low=mid+1;else up=mid-1;}//cout<<up<<' '<<low<<'*'<<endl;ans[low]=num[i];if(low>len) len++;/*****/}printf("Case %d:\n",k);if(len==1)printf("My king, at most 1 road can be built.");elseprintf("My king, at most %d roads can be built.",len);printf("\n");printf("\n");k++;}return 0;}