Create sparse_table.cpp

Changes

1 changed files (+17/-0)

• Data Structures/sparse_table.cpp (new)
  • @@ -0,0 +1,17 @@
    + class sparse_table { + private: int st[20][100000]; + public: + int log(int x) { return 32 - __builtin_clz(x) - 1; } + + sparse_table(int N, int A[]) { + for (int i = 0; i < N; i++) st[i][0] = A[i]; + for (int i = 0; i <= log(N); i++) { + for (int j = 0; j + (1 << i) < N; j++) st[i][j] = min(st[i - 1][j], st[i - 1][j + (1 << (i - 1))]); + } + } + + int query(int i, int j) { + int k = log(j - i + 1); + return min(st[k][i], st[k][j - (1 << k) + 1]); + } + };