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[HDU] 2795 Billboard [线段树区间求最值]

2024-08-04 17:51:51   221人阅读

Billboard

Time Limit: 20000/8000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 11861    Accepted Submission(s): 5223


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）
 

 

Recommend
lcy
 

题意:h*w的木板,放进一些1*L的物品,求每次放空间能容纳且最上边的位子
思路:每次找到最大值的位子,然后减去L
线段树功能:query:区间求最大值的位子

 

 1 #include<cstdio> 2 #include<string.h> 3 #include<algorithm> 4  5 #define clr(x,y) memset(x,y,sizeof(x)) 6 #define lson l,m,rt<<1 7 #define rson m+1,r,rt<<1|1 8  9 const int N=2e5+3511;10 using namespace std;11 12 int h,w,n,MAX[N<<2];13 14 void PushUp(int rt)15 {16     MAX[rt]=max(MAX[rt<<1],MAX[rt<<1|1]);17 }18 19 void build(int l,int r,int rt)20 {21     int m;22     23     MAX[rt]=w;24     if(l==r) {25         return;26     }27     28     m=(l+r)>>1;29     build(lson);30     build(rson);31 }32 33 int  query(int x,int l,int r,int rt)34 {35     int m,ret;36     if(l==r) {37         MAX[rt]-=x;38         return l;39     }40     m=(l+r)>>1;41     ret=(MAX[rt<<1]>=x) ? query(x,lson) : query(x,rson);42     PushUp(rt);43     return ret;44 }45 46 int main()47 {48     int x;49     while(~scanf("%d%d%d",&h,&w,&n)) {50         if(h>n) h=n;51         build(1,h,1);52         while(n--) {53             scanf("%d",&x);54             if(MAX[1]<x) puts("-1");55             else printf("%d\n",query(x,1,h,1));56             57         }58         59     }60     61     return 0;62 }

 

 

 

[HDU] 2795 Billboard [线段树区间求最值]


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