Hdu 2795 Billboard (line segment tree)
Question link: http://acm.hdu.edu.cn/showproblem.php? Pid = 1, 2795
Billboard
Time Limit: 20000/8000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission (s): 16673 Accepted Submission (s): 7056
Problem DescriptionAt 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, changesin 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 wowould always choose the topmost possible position for the announcement. Among all possible topmost positions she wowould 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 participant ants 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.
InputThere 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.
OutputFor 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 524333
Sample Output
1213-1
Authorhhanger @ zju
SourceHDOJ 2009 Summer Exercise (5)
Recommendlcy | We have carefully selected several similar problems for you: 1698 1542 1828 1540 question: an h * w announcement board should be posted on it. Enter the w value of 1 * wi, which is the announcement size. The following conditions must be met: 1. Try to go up and minimize the left of the same height. 2. Find the number of rows where the nth advertisement is located. 3. Output-1 if no proper position is attached. Solution: Use the line segment tree to obtain the maximum value of the interval and define a Max variable in the struct to indicate the vacant length of the row with the maximum number of vacancies in the interval. Compare it with the input length. First compare it on the left and then on the right. (That is, if the maximum value of the Left subtree is greater than that of the left subtree, the left subtree is queried. Otherwise, the right subtree is queried ).
For details, see the code.
# Include
# Include
# Include
Using namespace std; struct node {int l, r; int Max; // The vacant length of the row with the most vacancies in this interval} s [200000*4]; void InitTree (int l, int r, int k, int w) {s [k]. l = l; s [k]. r = r; s [k]. max = w; if (l = r) return; int mid = (l + r)/2; InitTree (l, mid, 2 * k, w ); initTree (mid + 1, r, 2 * k + 1, w);} void UpdataTree (int ww, int k) {if (s [k]. l = s [k]. r) {printf ("% d \ n", s [k]. l); s [k]. max-= ww; return;} if (ww <= s [k * 2]. max) UpdataTree (ww, k * 2); else UpdataTree ( Ww, k * 2 + 1); s [k]. Max = s [k * 2]. Max> s [k * 2 + 1]. Max? S [k * 2]. Max: s [k * 2 + 1]. Max;} int main () {int h, w, n; int ww; while (~ Scanf ("% d", & h, & w, & n) {if (h> n) // h <= n, h = n; InitTree (1, h, 1, w); for (int I = 1; I <= n; I ++) {scanf ("% d", & ww); if (s [1]. max> = ww) UpdataTree (ww, 1); else printf ("-1 \ n") ;}} return 0 ;}
