Update fenwick_tree.cpp

Changes

1 changed files (+3/-3)

• Data Structures/fenwick_tree.cpp
  • @@ -1,8 +1,8 @@
    template<typename T> class fenwick_tree { private: vector<T> FT; public: - fenwick_tree(int N) { FT.assign(N + 1, 0); } - void update(int x, T val) { if (x > 0) for (; x < FT.size(); x += x & -x) FT[x] += val; } - T query(int x) { T ret = 0; if (x > 0) for (; x > 0; x -= x & -x) ret += FT[x]; return ret; } + fenwick_tree(int N) { FT.assign(N + 5, 0); } + void update(int x, T val) { if (++x) for (; x < FT.size(); x += x & -x) FT[x] += val; } + T query(int x) { T ret = 0; if (++x) for (; x > 0; x -= x & -x) ret += FT[x]; return ret; } T query(int x, int y) { return query(y) - query(x - 1); } };