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