Solution of 11057 - Exact Sum

Problem Description
source:https://uva.onlinejudge.org/external/110/11057.html

Peter received money from his parents this week and wants to spend it all buying books. But he does not read a book so fast, because he likes to enjoy every single word while he is reading. In this way, it takes him a week to finish a book. 
          As Peter receives money every two weeks, he decided to buy two books, then he can read them until receive more money. As he wishes to spend all the money, he should choose two books whose prices summed up are equal to the money that he has. It is a little bit difficult to find these books, so Peter asks your help to find them.

Solution of 11044 - Searching for Nessy

Problem Description
source:https://uva.onlinejudge.org/external/110/11044.html

The Loch Ness Monsteris a mysterious and unidentified animal said to inhabit Loch Ness, a large deep freshwater loch near the city of Inverness in northern Scotland. Nessie is usually categorized as a type of lake monster. 

http://en.wikipedia.org/wiki/Loch_Ness_Monster 

In July 2003, the BBC reported an extensive investigation of Loch Ness by a BBC team, using 600 separate sonar beams, found no trace of any “sea monster” (i.e., any large animal, known or unknown) in the loch. The BBC team concluded that Nessie does not exist. Now we want to repeat the experiment. 
      Given a grid of n rows and m columns representing the loch, 6 ≤ n, m ≤ 10000, find the minimum number s of sonar beams you must put in the square such that we can control every position in the grid, with the following conditions:

Solution of 11034 - Ferry Loading IV

Problem Description
source:https://uva.onlinejudge.org/external/110/11034.html

Before bridges were common, ferries were used to transport cars across rivers. River ferries, unlike their larger cousins, run on a guide line and are powered by the river’s current. Cars drive onto the ferry from one end, the ferry crosses the river, and the cars exit from the other end of the ferry. 
         There is an l-meter-long ferry that crosses the river. A car may arrive at either river bank to be transported by the ferry to the opposite bank. The ferry travels continuously back and forth between the banks so long as it is carrying a car or there is at least one car waiting at either bank. Whenever the ferry arrives at one of the banks, it unloads its cargo and loads up cars that are waiting to cross as long as they fit on its deck. The cars are loaded in the order of their arrival; ferry’s deck accommodates only one lane of cars. The ferry is initially on the left bank where it broke and it took quite some time to fix it. In the meantime, lines of cars formed on both banks that await to cross the river.