poj2481

树状数组，难点在于处理相同区间，对于相同区间，只是把答案直接拷贝过来，并把其加入树状数组，不可以直接在树状数组中求和。

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
using namespace std;

#define maxn 100005

struct Interval
{
    int s, e;
    int pos;
} interval[maxn];

int n;
int ar[maxn];
int ans[maxn];

bool operator <(const Interval &a, const Interval &b)
{
    if (a.e == b.e)
        return a.s < b.s;
    return a.e > b.e;
}

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

void add(int i, int v)
{
    for (; i < maxn; ar[i] += v, i += lowbit(i))
        ;
}

int sum(int i)
{
    int s = 0;
    for (; i > 0; s += ar[i], i -= lowbit(i))
        ;
    return s;
}

int main()
{
    //freopen("t.txt", "r", stdin);
    while (scanf("%d", &n), n != 0)
    {
        memset(ar, 0, sizeof(ar));
        for (int i = 0; i < n; i++)
        {
            scanf("%d%d", &interval[i].s, &interval[i].e);
            interval[i].pos = i;
        }
        sort(interval, interval + n);
        for (int i = 0; i < n; i++)
        {
            if (i != 0 && interval[i].s == interval[i - 1].s && interval[i].e
                    == interval[i - 1].e)
            {
                ans[interval[i].pos] = ans[interval[i - 1].pos];
            }
            else
                ans[interval[i].pos] = sum(interval[i].s + 1);
            add(interval[i].s + 1, 1);
        }
        printf("%d", ans[0]);
        for (int i = 1; i < n; i++)
            printf(" %d", ans[i]);
        printf("\n");
    }
    return 0;
}