传送门:http://www.lydsy.com/JudgeOnline/problem.php?id=3685
【题解】
写个set+fread即可。
# include <set> # include <stdio.h> # include <string.h> # include <iostream> # include <algorithm> // # include <bits/stdc++.h> using namespace std; typedef long long ll; typedef long double ld; typedef unsigned long long ull; const int M = 5e5 + 10; const int mod = 1e9+7; # define RG register # define ST static namespace FIFO { char ch,B[1<<20],*S=B,*T=B; #define getc() (S==T&&(T=(S=B)+fread(B,1,1<<20,stdin),S==T)?0:*S++) #define isd(c) (c>='0'&&c<='9') int aa,bb;int F(){ while(ch=getc(),!isd(ch)&&ch!='-');ch=='-'?aa=bb=0:(aa=ch-'0',bb=1); while(ch=getc(),isd(ch))aa=aa*10+ch-'0';return bb?aa:-aa; } } #define gi FIFO::F() #define BUFSIZE 5000000 namespace fob {char b[BUFSIZE]={},*f=b,*g=b+BUFSIZE-2;} #define pob (fwrite(fob::b,sizeof(char),fob::f-fob::b,stdout),fob::f=fob::b,0) #define pc(x) (*(fob::f++)=(x),(fob::f==fob::g)?pob:0) struct foce {~foce() {pob; fflush(stdout);}} _foce; namespace ib {char b[100];} inline void pint(int x) { if(x==0) {pc(48); return;} if(x<0) {pc('-'); x=-x;} //如果有负数就加上 char *s=ib::b; while(x) *(++s)=x%10, x/=10; while(s!=ib::b) pc((*(s--))+48); } int n, m; set<int> s; set<int>::iterator it; int main() { int opt, x; n = gi, m = gi; while(m--) { opt = gi; if(opt == 1) { x = gi; s.insert(x); } if(opt == 2) { x = gi; it = s.find(x); if(it != s.end()) s.erase(it); } if(opt == 3) { if(s.size() == 0) pint(-1); else pint(*s.begin()); pc(10); } if(opt == 4) { if(s.size() == 0) pint(-1); else pint(*--s.end()); pc(10); } if(opt == 5) { x = gi; it = s.lower_bound(x); if(it == s.begin()) pint(-1); else pint(*--it); pc(10); } if(opt == 6) { x = gi; it = s.upper_bound(x); if(it == s.end()) pint(-1); else pint(*it); pc(10); } if(opt == 7) { x = gi; it = s.find(x); if(it != s.end()) pint(1); else pint(-1); pc(10); } } return 0; }