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hdu2795 Billboard（線段樹）

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hdu2795 Billboard（線段樹）

Billboard

Time Limit: 20000/8000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 16647 Accepted Submission(s): 7037

Problem Description At the entrance to the university, there is a huge rectangular billboard of size h*w (h is its height and w is its width). The board is the place where all possible announcements are posted: nearest programming competitions, changes in the dining room menu, and other important information.

On September 1, the billboard was empty. One by one, the announcements started being put on the billboard.

Each announcement is a stripe of paper of unit height. More specifically, the i-th announcement is a rectangle of size 1 * wi.

When someone puts a new announcement on the billboard, she would always choose the topmost possible position for the announcement. Among all possible topmost positions she would always choose the leftmost one.

If there is no valid location for a new announcement, it is not put on the billboard (that's why some programming contests have no participants from this university).

Given the sizes of the billboard and the announcements, your task is to find the numbers of rows in which the announcements are placed.
Input There are multiple cases (no more than 40 cases).

The first line of the input file contains three integer numbers, h, w, and n (1 <= h,w <= 10^9; 1 <= n <= 200,000) - the dimensions of the billboard and the number of announcements.

Each of the next n lines contains an integer number wi (1 <= wi <= 10^9) - the width of i-th announcement.
Output For each announcement (in the order they are given in the input file) output one number - the number of the row in which this announcement is placed. Rows are numbered from 1 to h, starting with the top row. If an announcement can't be put on the billboard, output "-1" for this announcement.
Sample Input

Sample Output

Author hhanger@zju
Source HDOJ 2009 Summer Exercise（5）
題意：一塊h*w的廣告板上貼廣告，每條廣告均為1*wi；如果能貼，輸出貼的位置（即第幾行，位置盡量靠上，靠左）；否則輸出-1. 分析：首先，葉子節點只有min(n, h)個，不要被10^9嚇到；然後把每行的空間存進樹，每貼一條廣告就刪除相應的空間。

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
using namespace std;
const double eps = 1e-6;
const double pi = acos(-1.0);
const int INF = 0x3f3f3f3f;
const int MOD = 1000000007;
#define ll long long
#define CL(a,b) memset(a,b,sizeof(a))
#define MAXN 200010

struct node
{
    int a,b,r;
}t[MAXN*4];
int h,w,n;

void build(int x, int y, int num)
{
    t[num].a = x;
    t[num].b = y;
    t[num].r = w;
    if(x == y) return ;
    int mid = (x+y)>>1;
    build(x, mid, num<<1);
    build(mid+1, y, num<<1|1);
}

int query(int x, int num)
{
    if(t[num].a == t[num].b)
    {
        t[num].r -= x;
        return t[num].a;
    }
    else
    {
        int sum1=0, sum2=0;
        if(x <= t[num<<1].r) sum1 = query(x, num<<1);
        else if(x <= t[num<<1|1].r) sum2 = query(x, num<<1|1);
        t[num].r = max(t[num<<1].r, t[num<<1|1].r);
        return sum1+sum2;
    }
}

int main()
{
    while(scanf("%d%d%d",&h,&w,&n)==3)
    {
        if(h > n) h = n;
        build(1, h, 1);
        int k;
        for(int i=1; i<=n; i++)
        {
            scanf("%d",&k);
            if(k <= t[1].r) printf("%d\n",query(k, 1));
            else printf("-1\n");
        }
    }
    return 0;
}