CCF/CSP-201812-3-CIDR合并

按照题意模拟，但是只有90，不想找bug了，毕竟算法不是自己想的，找起来也麻烦。

#include<bits/stdc++.h>
using namespace std;
#define inf 0x3f3f3f3f
#define LL long long
#define pui pair<unsigned int,int>
#define mp make_pair
#define x first
#define y second

const int maxn=1000005;
pui a[maxn];
vector<pui>ans;
int n,q[4]={24,16,8,0},l[]={0,8,16,24,32};
int base[]={(1<<24),(1<<16),(1<<8),1};
ostream& operator << (ostream& out,pui& u){
    for(int i=0;i<4;++i){
        out<<u.x/base[i]%base[2];
        if(i<3)out<<".";
    }out<<"/"<<u.y;
    return out;
}
bool issub(int i,int j){
    if(a[i].y==a[j].y){
        if(a[i].x==a[j].x){return 1;}
        else{return 0;}
    }else if(a[i].y>a[j].y)return 0;
    else{
        if((a[j].x>>(32-a[i].y))==(a[i].x>>(32-a[i].y)))return 1;
        else return 0;
    }
}
bool ok(pui A,pui B){
    pui tmp;tmp.x=A.x;tmp.y=A.y-1;
    if(A.y==B.y &&tmp.y>=0  && ((A.x>>(32-A.y)>>1)==(B.x>>(32-A.y)>>1))
       && (((A.x>>(32-A.y))&1)^((B.x>>(32-A.y))&1))==1 ) return 1;
    return 0;
}
int main(){
    string str;
    ios::sync_with_stdio(false);
    cin>>n;
    for(int i=0;i<n;++i){
        a[i].y=a[i].x=0;
        cin>>str;
        int pos=str.find('/'),cur=0,sz=str.size();
        unsigned tmp=0;
        for(int ii=0;ii<sz&&str[ii]!='/';++ii){
            if(str[ii]=='.'){
            a[i].x+=(tmp<<q[cur++]);
            tmp=0;
            }else{
            tmp=tmp*10+(str[ii]-'0');
            }
        }
        if(tmp){
            a[i].x+=(tmp<<q[cur++]);
        }
        if(pos!=string::npos){
            for(int iii=pos+1;iii<sz;++iii) a[i].y=a[i].y*10+(str[iii]-'0');
        }else{
            a[i].y=l[cur];
        }
    }
    sort(a,a+n);
    for(int i=0;i<n;++i){
        if(a[i].y==-1)continue;
        int k=1;
        while(i+k<=n && issub(i,i+k)) a[i+k].y=-1,k++;
        i=i+k-1;
    }

    for(int i=0;i<n;++i){
        if(a[i].y==-1){continue;}
        pui B=a[i];
        while(ans.size()&&ok(ans.back(),B)){
            B.x=ans.back().x;B.y=ans.back().y-1;
            ans.pop_back();
        }
        ans.push_back(B);
    }
    for(pui u:ans) cout<<u<<endl;
    return 0;
}