110 lines
2.5 KiB
Java
110 lines
2.5 KiB
Java
public class FenwickTreeExtended {
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// T[i] += value
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public static void add(int[] t, int i, int value) {
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for (; i < t.length; i |= i + 1)
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t[i] += value;
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}
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// sum[0..i]
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public static int sum(int[] t, int i) {
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int res = 0;
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for (; i >= 0; i = (i & (i + 1)) - 1)
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res += t[i];
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return res;
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}
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public static int[] createFromArray(int[] a) {
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int[] res = new int[a.length];
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for (int i = 0; i < a.length; i++) {
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res[i] += a[i];
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int j = i | (i + 1);
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if (j < a.length)
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res[j] += res[i];
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}
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return res;
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}
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// sum[a..b]
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public static int sum(int[] t, int a, int b) {
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return sum(t, b) - sum(t, a - 1);
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}
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public static int get(int[] t, int i) {
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int res = t[i];
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if (i > 0) {
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int lca = (i & (i + 1)) - 1;
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for (--i; i != lca; i = (i & (i + 1)) - 1)
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res -= t[i];
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}
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return res;
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}
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public static void set(int[] t, int i, int value) {
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add(t, i, -get(t, i) + value);
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}
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///////////////////////////////////////////////////////
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// interval add
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public static void add(int[] t, int a, int b, int value) {
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add(t, a, value);
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add(t, b + 1, -value);
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}
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// point query
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public static int get1(int[] t, int i) {
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return sum(t, i);
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}
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///////////////////////////////////////////////////////
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///////////////////////////////////////////////////////
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// interval add
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public static void add(int[] t1, int[] t2, int a, int b, int value) {
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add(t1, a, value);
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add(t1, b, -value);
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add(t2, a, -value * (a - 1));
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add(t2, b, value * b);
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}
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// interval query
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public static int sum(int[] t1, int[] t2, int i) {
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return sum(t1, i) * i + sum(t2, i);
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}
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///////////////////////////////////////////////////////
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// Returns min(p|sum[0,p]>=sum)
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public static int lower_bound(int[] t, int sum) {
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--sum;
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int pos = -1;
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for (int blockSize = Integer.highestOneBit(t.length); blockSize != 0; blockSize >>= 1) {
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int nextPos = pos + blockSize;
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if (nextPos < t.length && sum >= t[nextPos]) {
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sum -= t[nextPos];
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pos = nextPos;
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}
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}
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return pos + 1;
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}
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// Usage example
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public static void main(String[] args) {
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int[] t = new int[10];
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set(t, 0, 1);
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add(t, 9, -2);
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System.out.println(-1 == sum(t, 0, 9));
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t = createFromArray(new int[]{1, 2, 3, 4, 5, 6});
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for (int i = 0; i < t.length; i++)
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System.out.print(get(t, i) + " ");
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System.out.println();
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t = createFromArray(new int[]{0, 0, 1, 0, 0, 1, 0, 0});
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System.out.println(5 == lower_bound(t, 2));
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int[] t1 = new int[10];
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int[] t2 = new int[10];
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add(t1, t2, 0, 9, 1);
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add(t1, t2, 0, 0, -2);
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System.out.println(sum(t1, t2, 9));
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}
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}
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