URAL 1028 Stars

URAL_1028

    将点排序后依次插入线段树，就可以将计算星星等级转化成区间求和的问题了，于是用线段树支持单点修改和区间求和即可。

#include<stdio.h>

#include<string.h>

#include<stdlib.h>

#define MAXD 15010

#define MAXX 32010

struct Point

{

    int x, y;

}p[MAXD];

const int D = 32000;

int N, num[4 * MAXX], h[MAXD];

int cmp(const void *_p, const void *_q)

{

    Point *p = (Point *)_p, *q = (Point *)_q;

    if(p->y == q->y)

        return p->x < q->x ? -1 : 1;

    return p->y < q->y ? -1 : 1;

}

void init()

{

    int i, j, k;

    for(i = 0; i < N; i ++)

        scanf("%d%d", &p[i].x, &p[i].y);

    qsort(p, N, sizeof(p[0]), cmp);

    memset(num, 0, sizeof(num));

}

void update(int cur)

{

    num[cur] = num[cur << 1] + num[(cur << 1) | 1];

}

int Search(int cur, int x, int y, int s, int t)

{

    int mid = (x + y) >> 1, ls = cur << 1, rs = (cur << 1) | 1;

    if(x >= s && y <= t)

        return num[cur];

    if(mid >= t)

        return Search(ls, x, mid, s, t);

    else if(mid + 1 <= s)

        return Search(rs, mid + 1, y, s, t);

    else

        return Search(ls, x, mid, s, t) + Search(rs, mid + 1, y, s, t);

}

void refresh(int cur, int x, int y, int k)

{

    int mid = (x + y) >> 1, ls = cur << 1, rs = (cur << 1) | 1;

    if(x == y)

    {

        ++ num[cur];

        return ;

    }

    if(k <= mid)

        refresh(ls, x, mid, k);

    else

        refresh(rs, mid + 1, y, k);

    update(cur);

}

void solve()

{

    int i, j, k;

    memset(h, 0, sizeof(h));

    for(i = 0; i < N; i ++)

    {

        k = Search(1, 0, D, 0, p[i].x);

        ++ h[k];

        refresh(1, 0, D, p[i].x);

    }

    for(i = 0; i < N; i ++)

        printf("%d\n", h[i]);

}

int main()

{

    while(scanf("%d", &N) == 1)

    {

        init();

        solve();

    }

    return 0;

}