CareerCup

Given two strings s1, s2, write a function that returns true if s2 is a special substring s1. A special substring s2 is such that the s1 contains s2 where each character in s2 appears in sequence in s1, but there can be any characters in s1 in between the sequence.

Example:

isSpecialSubstring('abcdefg', 'abc') => true
isSpecialSubstring('abcdefg', 'acg') => true
isSpecialSubstring('abcdefg', 'acb') => false;


The first two are abc and acg appears in 'abcdefg' in that order, although there might be multiple chars between the next character in s2.

The last one is false, because in 'acb' the character 'b' appears before the character 'c' in 'abcdefg'

Hope thats clear.

The input consists of N cases(equal to about 10000). The first line of the input contains only positive integer N. Then follow the cases. Each case consists of exactly one line with two positive integers separated by space. These are the numbers whose reverse you have to add

The input consists of N cases(equal to about 10000). The first line of the input contains only positive integer N. Then follow the cases. Each case consists of exactly one line with two positive integers separated by space. These are the numbers whose reverse you have to add

create a class of integer collection,
3 APIs:
append(int x),
get(int idx),
add_to_all(int x)，
in O(1) time。

Follow-up:
implement
multiply_to_all(int x)

e.g.
insert(1)
insert(2)
add_to_all(5)
insert(3)
get(0) -> returns 6
get(2) -> return 3
multiply_to_all(10)
insert(4)
get(1) -> returns 70
get(2) -> returns 30
get(3) -> returns 4

Lonely Pixel
Given an N x M image with black pixels and white pixels, if a pixel is the only one in its color throughout its entire row and column, then it is a lonely pixel. Find the number of lonely pixels in black from the image. (O(NM))