SUBSEQ - Counting Subsequences
"47 is the quintessential random number," states the 47 society. And there might be a grain of truth in that.
For example, the first ten digits of the Euler's constant are:
2 7 1 8 2 8 1 8 2 8
And what's their sum? Of course, it is 47.
Try walking around with your eyes open. You may be sure that soon you will start discovering occurences of the number 47 everywhere.
You are given a sequence S of integers we saw somewhere in the nature. Your task will be to compute how strongly does this sequence support the above claims.
We will call a continuous subsequence of S interesting if the sum of its terms is equal to 47.
E.g., consider the sequence S = (24, 17, 23, 24, 5, 47). Here we have two interesting continuous subsequences: the sequence (23, 24) and the sequence (47).
Given a sequence S, find the count of its interesting subsequences.
The first line of the input file contains an integer T specifying the number of test cases. Each test case is preceded by a blank line.
The first line of each test case contains the length of a sequence N. The second line contains N space-separated integers : the elements of the sequence.
For each test case output a single line containing a single integer : the count of interesting subsequences of the given sentence.
Input: 2 13 2 7 1 8 2 8 1 8 2 8 4 5 9 7 2 47 10047 47 1047 47 47 Output: 3 4Note: the input file will not exceed 4MB.
You had the time for writing the entire story of the number 47, but not for mentioning the constraints of the problem?
A.C. using prefix sum array
java.util.HashMap Costs TLE..!! Any other alternative..?
Beware,Numbers can be negative.use of binary search gives WA..Last edit: 2017-01-04 08:55:52
No description of constraints!
All values fit into 32bit integer, for array size i used 2^20. If you can try avoid using stl maps because they lead to high cache miss. If you use maps dont allocate new map for each test, rather try erasing elements from current map when you dont need them.
getting TLE despite of using map. No clue regarding how to optimize. Please specify the range for input.
What are the ranges of values in sequence ??
getting TLE,do not know how to optimise.