Chef and Line
All submissions for this problem are available.
Read problems statements in Mandarin chinese, Russian and Vietnamese as well.
Chef has a sequence A with length N and a line given by the equation y(x) = k · x + b. Let us say that an element Aj is reachable from another element Ai if the point (Ai, Aj) is lying above or on the line y(x), i.e. if Aj ≥ k · Ai + b.
Consider an arbitrary subsequence of A; let's denote it by B. Subsequence B is called good if its elements can be reordered in such a way that for each valid i, Bi+1 is reachable from Bi.
Chef asked you to compute the maximum possible length of a good subsequence. Can you help him?
- The first line of the input contains a single integer T denoting the number of test cases. The description of T test cases follows.
- The first line of each test case contains three space-separated integers N, k and b.
- The second line contains N space-separated integers A1, A2, ..., AN.
For each test case, print a single line containing one integer — the length of the longest good subsequence of A.
- 1 ≤ T ≤ 5000
- 1 ≤ N ≤ 100000
- 0 ≤ k, b ≤ 109
- 0 ≤ Ai ≤ 109 for each valid i
- 1 ≤ sum of N over all test cases ≤ 200000
Input: 1 5 4 1 100 2 4 17 8 Output: 3
Example case 1: We can choose the subsequence (100, 4, 17) and reorder it to get the sequence (4, 17, 100). In this sequence, 17 is reachable from 4 because 4 · 4 + 1 = 17 ≤ 17 and 100 is reachable from 17 because 4 · 17 + 1 = 69 ≤ 100. Hence, (100, 4, 17) is a good subsequence; there is no good subsequence of A with length 4 or more, so the answer is 3.
|Tags||cook91, greedy, mgch, simple, sorting|
|Time Limit:||0.5 sec|
|Source Limit:||50000 Bytes|
|Languages:||C, CPP14, JAVA, PYTH, PYTH 3.6, PYPY, CS2, PAS fpc, PAS gpc, RUBY, PHP, GO, NODEJS, HASK, rust, SCALA, swift, D, PERL, FORT, WSPC, ADA, CAML, ICK, BF, ASM, CLPS, PRLG, ICON, SCM qobi, PIKE, ST, NICE, LUA, BASH, NEM, LISP sbcl, LISP clisp, SCM guile, JS, ERL, TCL, kotlin, PERL6, TEXT, SCM chicken, CLOJ, COB, FS|
Fetching successful submissions