public class FenwickTree3D { public static void add(int[][][] t, int x, int y, int z, int value) { for (int i = x; i < t.length; i |= i + 1) for (int j = y; j < t[0].length; j |= j + 1) for (int k = z; k < t[0][0].length; k |= k + 1) t[i][j][k] += value; } // sum[(0, 0, 0), (x, y, z)] public static int sum(int[][][] t, int x, int y, int z) { int res = 0; for (int i = x; i >= 0; i = (i & (i + 1)) - 1) for (int j = y; j >= 0; j = (j & (j + 1)) - 1) for (int k = z; k >= 0; k = (k & (k + 1)) - 1) res += t[i][j][k]; return res; } public static void main(String[] args) { int[][][] t = new int[10][20][30]; add(t, 0, 0, 0, 1); add(t, 9, 19, 29, -2); System.out.println(-1 == sum(t, 9, 19, 29)); } }