为了让大家都有抽奖的机会，只需要复制粘贴以下代码（并且稍微填下空）即可 AC：
（我超良心的）
#include <algorithm>
#include <iostream>
#include <cstring>
#include <climits>
#include <cstdio>
#include <vector>
#include <cstdlib>
#include <ctime>
#include <cmath>
#include <queue>
#include <stack>
#include <map>
#include <set>
#define fi first
#define lc (x<<1)
#define se second
#define U unsigned
#define rc (x<<1|1)
#define Re register
#define LL long long
#define MP std::make_pair
#define CLR(i,a) memset(i,a,sizeof(i))
#define FOR(i,a,b) for(Re int i = a;i <= b;++i)
#define ROF(i,a,b) for(Re int i = a;i >= b;--i)
#define SFOR(i,a,b,c) for(Re int i = a;i <= b;i+=c)
#define SROF(i,a,b,c) for(Re int i = a;i >= b;i-=c)
#define DEBUG(x) std::cerr << #x << '=' << x << std::endl
const int MAXN = 1000000+5;
int N,maxL;
std::set<std::pair<int,int> > L;
inline int calc(){
// 返回 set 中所有线段的并长度。(每个 pair 表示一个线段[first,second]
}
int main(){
scanf("%d%d",&N,&maxL);
while(N--){
int opt,x,y;
scanf("%d%d%d",&opt,&x,&y);
if(opt == 1){
if(L.find(MP(x,y)) != L.end()) continue;
L.insert(MP(x,y));
}
if(opt == 2){
if(L.find(MP(x,y)) == L.end()) continue;
L.erase(MP(x,y));
}
if(opt == 3){
printf("%d\n",calc());
}
}
return 0;
}
