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【线段树四】HDU 2795 Billboard

2024-07-01 23:22:29   231人阅读

Billboard

Time Limit: 20000/8000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 9045    Accepted Submission(s): 4021


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
3 5 5
2
4
3
3
3
 

Sample Output
1
2
1
3
-1
 

Author
hhanger@zju
 

Source
HDOJ 2009 Summer Exercise（5）

来源： <http://acm.hdu.edu.cn/showproblem.php?pid=2795>
  

题意：

知识点：区间范围取最大值。
叶子节点代表广告牌的宽度

#include<stdio.h>
#include <algorithm>

using namespace std;
#define MAXN 200000
int t[MAXN*4];
int h,w,n;
void PushUp(int index){
    t[index]=max(t[index*2],t[index*2+1]);
}
void build(int l,int r,int index){
    if(l==r){
        t[index]=w;
        return ;
    }
    int mid=(l+r)/2;
    build(l,mid,index*2);
    build(mid+1,r,index*2+1);
    PushUp(index);
}
int Query(int width,int l,int r,int index){
    if(l==r){
        t[index]-=width;
        return l;//返回所在层数
    }
    int mid=(l+r)/2;
    int hh=0;
    if(t[index*2]>=width)
        hh=Query(width,l,mid,index*2);
    else
        hh=Query(width,mid+1,r,index*2+1);
    PushUp(index);
    return hh;

}
int main(){
    while(~scanf("%d%d%d",&h,&w,&n)){
        if(h>n)//这里如果广告牌的高度大于通告的个数的话
        h=n;
        build(1,h,1);//是以广告牌的高度为范围建树
        int wi;
        for(int i=1;i<=n;i++){
        scanf("%d",&wi);
        if(t[1]<wi)
            printf("-1\n");
        else
            printf("%d\n",Query(wi,1,h,1));

        }
    }
    return 0;
}







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