HDU 2852 KiKi's K-Number(离线+树状数组)

题目链接

省赛训练赛上一题，貌似不难啊。当初，没做出。离线+树状数组+二分。

#include <cstdio>
#include <cstring>
#include <iostream>
using namespace std;
#define N 100000
int p[100100];
int qur[300001][3];
int lowbit(int t)
{
    return t&(-t);
}
void insert(int t,int d)
{
    while(t <= N)
    {
        p[t] += d;
        t += lowbit(t);
    }
}
int getsum(int t)
{
    int sum = 0;
    while(t)
    {
        sum += p[t];
        t -= lowbit(t);
    }
    return sum;
}
int bin(int x)
{
    int str,end,mid;
    if(x > getsum(N))
    return -1;
    str = 1;
    end = N;
    while(str < end)
    {
        mid = (str + end)/2;
        if(getsum(mid) < x)
        str = mid + 1;
        else
        end = mid;
    }
    return str;
}
int main()
{
    int n,i;
    while(scanf("%d",&n)!=EOF)
    {
        memset(p,0,sizeof(p));
        for(i = 0;i < n;i ++)
        {
           scanf("%d",&qur[i][0]);
           if(qur[i][0] == 0||qur[i][0] == 1)
           scanf("%d",&qur[i][1]);
           else
           scanf("%d%d",&qur[i][1],&qur[i][2]);
        }
        for(i = 0;i < n;i ++)
        {
            if(qur[i][0] == 0)
            insert(qur[i][1],1);
            else if(qur[i][0] == 1)
            {
                if(getsum(qur[i][1])-getsum(qur[i][1]-1) > 0)
                insert(qur[i][1],-1);
                else
                printf("No Elment!
");
            }
            else
            {
                int flag;
                flag = bin(getsum(qur[i][1])+qur[i][2]);
                if(flag == -1)
                printf("Not Find!
");
                else
                printf("%d
",flag);
            }
        }
    }
    return 0;
}