update fenwick tree

Changes

1 changed files (+1/-1)

• Data Structures/fenwick_tree.cpp
  • @@ -4,5 +4,5 @@ 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; } - T query(int x, int y) { return query(y) - (x == 1 ? 0 : query(x - 1)); } + T query(int x, int y) { return query(y) - query(x - 1); } };