hdu 2852 KiKi's K-Number（树状数组+二分）

/*
Problem ID:
meaning:
Analyzing:
*/
#include <iostream>
#include <algorithm>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<cstring>
#include<vector>
#include<queue>

using namespace std;
typedef struct even{int y1,y2,x;}even;

#define clr(A,k) memset(A,k,sizeof(A))
#define FOR(i,s,t) for(int i=(s); i<(t); i++)
#define LL long long
#define BUG puts("here!!!")
#define print(x) printf("%d\n",x)
#define STOP system("pause")
#define eps 1e-8
#define PI acos(-1.0)
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define maxn 100001
#define lowbit(x) x&(-x)
LL gcd(LL a,LL b) {return a?gcd(b%a,a):b;}
priority_queue<int>q1;
int A[maxn],C[maxn];
void update(int pos,int val){
    while(pos<maxn){
        C[pos]+=val;
        pos+=lowbit(pos);
    }
}
int query(int x){
    int ret=0;
    while(x>0){
        ret+=C[x];
        x-=lowbit(x);
    }
    return ret;
}
int binsearch(int a,int k){
    int l=a+1;
    int r=maxn-1;
    int ans=maxn;
    int s1=query(a);
    while(l<=r){
        int m=(l+r)>>1;
        int s2=query(m);
        if(s2-s1>=k){
            r=m-1;
            if(m<ans) ans=m;
        }
        else {
            l=m+1;
        }
    }
    return ans;
}
int main(){
    int m,op,a,k,e;
    while(~scanf("%d",&m)){
        clr(A,0);
        clr(C,0);
        int len=0;
        while(m--){
            scanf("%d",&op);
            if(op==0){
                scanf("%d",&e);
                if(A[e]==0) update(e,1);
            }
            else if(op==1) {
                scanf("%d",&e);
                if(query(e)-query(e-1)==0) puts("No Elment!");
                else
                    update(e,-1);
            }
            else if(op==2){
                scanf("%d%d",&a,&k);
                int ret=binsearch(a,k);
                if(ret==maxn) puts("Not Find!");
                else printf("%d\n",ret);
            }
        }
    }
return 0;
}