can any one help on segment trees ,how to use segment tree in this problem???
read about segment trees with lazy propagation 
i tried a lot but can’t seem to implement it with this problem if you can help a bit more…
Try using arrays , instead of binary tree for constructing segment tree
@sakuag333 why we should use arrays instead of binary tree??kindly help… http://www.codechef.com/viewsolution/5271503 …my soln of flipcoin using binary tree is giving right answer for sample test cases and random inputs but wrong answer on submission… Kindly help