hdu 2852 KiKi's K-Number

树状数组+二分查找

/* ***********************************************
Author        :xryz
Email         :523689985@qq.com
Created Time  :4-26 22:23:18
File Name     :KiKi's K-Number.cpp
************************************************ */

#include <stdio.h>
#include <string.h>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <string>
#include <math.h>
#include <stdlib.h>
#include <time.h>
using namespace std;

const int N=100000+5;
int p[N];

int lowbit(int x)
{
    return x&-x;
}

int sum(int x)
{
    int ret=0;
    while(x>0)
    {
        ret+=p[x];
        x-=lowbit(x);
    }
    return ret;
}

void add(int x,int d)
{
    while(x<=N)
    {
        p[x]+=d;
        x+=lowbit(x);
    }
}

int binaryfind(int a,int k)
{
    int low=a+1,high=N-1,mid;
    int t=sum(a);
    int ans=N,num;
    while(high>=low)
    {
        mid=(low+high)>>1;
        num=sum(mid);
        if(num-t>=k)
        {
            high=mid-1;
            if(mid<ans)
                ans=mid;
        }
        else low=mid+1;
    }
    return ans;
}
int main()
{
    int k,m,t,a;
    while(~scanf("%d",&k))
    {
        memset(p,0,sizeof(p));
        while(k--)
        {
            scanf("%d",&m);
            if(m==0)
            {
                scanf("%d",&t);
                add(t,1);
            }
            else if(m==1)
            {
                scanf("%d",&t);
                if(sum(t)-sum(t-1)>=1)
                {
                    add(t,-1);
                }
                else
                    printf("No Elment!\n");
            }
            else if(m==2)
            {
                scanf("%d%d",&a,&t);
                int f=binaryfind(a,t);
                if(f==N)
                    printf("Not Find!\n");
                else printf("%d\n",f);
            }
        }
    }
    return 0;
}

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