Category: tricks

The problem is from codeforces: http://www.codeforces.com/contest/265/problem/B This problem is not difficult, but it took me nearly 1:30 hr to get it right during the contest. I thought at first, the …

The problem is from codeforces: http://codeforces.com/contest/263/problem/B Sort the squares by sizes then we will easily derive the answer. If there is a point in the smallest square, it must be …

The problem is from codeforces: http://codeforces.com/contest/263/problem/A It looks complex but in fact it is not. There is only one ‘1’ element in this fixed-5X5 matrix. The shortest path to the …

I participated in Codeforces online contest yesterday and was trying to solve this problemusing DFS (Depth-First-Search). I got somehow stuck in the WA3 (Wrong Answer Test 3). I checked …

The problem is from codeforces: http://www.codeforces.com/problemset/problem/262/B Two hints used to solve this problem are greedy and sorted numbers. The greedy approach turns negative numbers one by one in non-decreasing order …