CSP2018年12月 CIDR合并

#include<bits/stdc++.h>
#define N 100010
#define LL unsigned int
using namespace std;

int n,m=0;
char x[30];
vector<int> th;
bool f[N];
struct node
{
	LL a;int b,c;
	bool operator < (const node z) const
	{
		return a==z.a?b<z.b:a<z.a;
	}
}c[N];

int pp(char *s)
{
	th.clear();
	int t=-1;
	for (int i=0;s[i];i++)
	{
		if (s[i]=='.') th.push_back(i);
		if (s[i]=='/') t=i;
	}
	return t;
}

void pre(char *s)
{
	int fg=pp(s),b;
	LL a=0;
	if (fg>0) b=atoi(s+fg+1),s[fg]=0;else
		b=(1+th.size())*8;
	int st=-1;
	for (int i=0;i<=th.size();i++)
	{
		int x=atoi(s+st+1);
		a=a+((LL)x<<((3-i)*8));
		if (th.size()>i) st=th[i];
	}
	c[++m]=node{a,b,32-b};
}

void pri(node c)
{
	LL a=c.a;
	printf("%d.%d.%d.%d/%d\n",a>>24,(a>>16)%256,(a>>8)%256,a%256,c.b);
}

int main()
{
	scanf("%d ",&n);
	for (int i=1;i<=n;i++)
	{
		scanf("%s",x);
		pre(x);
	}
	sort(c+1,c+n+1);
	int st=1;
	for (int i=2;i<=n;i++)
	{
		if (c[st].b<=c[i].b && (c[st].a>>c[st].c)==(c[i].a>>c[st].c)) f[i]=true;else
			st=i;
	}
	stack<node> sta,stb;
	for (int i=n;i>0;i--) if (!f[i]) stb.push(c[i]);
	while(!stb.empty())
	{
		if (sta.empty())
		{
			sta.push(stb.top());
			stb.pop();
		}else
		{
			node a=sta.top(),b=stb.top();
			if (a.b==b.b && (b.a>>b.c)-(a.a>>a.c)==1 && (b.a>>b.c+1)==(a.a>>a.c+1))
			{
			    sta.pop();
                stb.pop();
                stb.push(node{a.a,a.b-1,a.c+1});
			}else
			{
				sta.push(b);
				stb.pop();
			}
		}
	}
	vector<node>ans;
	while(!sta.empty())
	{
		ans.push_back(sta.top());
		sta.pop();
	}
	sort(ans.begin(),ans.end());
	for (int i=0;i<ans.size();i++)pri(ans[i]);
}