IMPLEMENTATION OF SEGMENT TREE About Segment tree- A Segment Tree is a data structure that allows answering range queries over an array effectively, while still being flexible enough to allow modifying the array. This includes finding the sum of consecutive array elements a[l…r], or finding the minimum element in a such a range in O(logn) time. Between answering such queries the Segment Tree allows modifying the array by replacing one element, or even change the elements of a whole subsegment (e.g. assigning all elements a[l…r] to any value, or adding a value to all element in the subsegment).
In general a Segment Tree is a very flexible data structure, and a huge number of problems can be solved with it. Additionally it is also possible to apply more complex operations and answer more complex queries (see Advanced versions of Segment Trees). In particular the Segment Tree can be easily generalized to larger dimensions. For instance with a two-dimensional Segment Tree you can answer sum or minimum queries over some subrectangle of a given matrix. However only in O(log2n) time.
One important property of Segment Trees is, that they require only a linear amount of memory. The standard Segment Tree requires 4n vertices for working on an array of size n.