HDOJ 4006 The kth great number

这道题来自于 The 36th ACM/ICPC Asia Regional Dalian Site —— Online Contest

线段树求第 k 大值，包含修改和询问；

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Problem Description

Xiao Ming and Xiao Bao are playing a simple Numbers game. In a round Xiao Ming can choose to write down a number, or ask Xiao Bao what the kth great number is. Because the number written by Xiao Ming is too much, Xiao Bao is feeling giddy. Now, try to help Xiao Bao.

 

Input

There are several test cases. For each test case, the first line of input contains two positive integer n, k. Then n lines follow. If Xiao Ming choose to write down a number, there will be an " I" followed by a number that Xiao Ming will write down. If Xiao Ming choose to ask Xiao Bao, there will be a "Q", then you need to output the kth great number.

 

Output

The output consists of one integer representing the largest number of islands that all lie on one line.

 

Sample Input

8 3 I 1 I 2 I 3 Q I 5 Q I 4 Q

 

Sample Output

1 2 3

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# include <stdio.h>
# include <string.h>

# define N 1000005

int n, k, D;
int cnt[4 * N];

void update(int i)
{
    for (i += D; i ^ 1; i >>= 1)
    {
        cnt[i >> 1] = cnt[i] + cnt[i ^ 1];
    }
}

int query(int p)
{
    int i;
    
    for (i = 1; i < D; )
    {
        i = i << 1 | 1;
        if (p > cnt[i]) p -= cnt[i], i = i ^ 1;
    }
    
    return i - D;
}

void init(void)
{
    int i;

    for (D = 1; D < N; D <<= 1) ;
    for (i = 0; i < 2*D+2; ++i)
        cnt[i] = 0;
}

void solve(void)
{
    int i, val;
    char s[5];

    for (i = 1; i <= n; ++i)
    {
        scanf("%s", s);
        switch(s[0])
        {
        case 'I': {scanf("%d", &val); ++cnt[val+D]; update(val); break;}
        case 'Q': {printf("%d\n", query(k)); break;}
        }
    }
}

int main()
{
    while (~scanf("%d%d", &n, &k))
    {
        init();
        solve();
    }

    return 0;
}

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