@Test
public void testFenwickTree() {
nums = new int[] {3, 4, 9, 1, 4, 7, 6, 0};
testClass = new FenwickTree(nums);
testRangeSum();
int val = +3;
int updateIdx = 4;
nums[updateIdx] += val;
testClass.updateTree(updateIdx, val);
testRangeSum();
val = -6;
updateIdx = 3;
nums[updateIdx] += val;
testClass.updateTree(updateIdx, val);
testRangeSum();
val = 7;
updateIdx = 0;
nums[updateIdx] -= val;
testClass.updateTree(updateIdx, -val);
val = -4;
updateIdx = 1;
nums[updateIdx] += val;
testClass.updateTree(updateIdx, val);
testRangeSum();
}
public static FenwickTree fenwickTree(long[] A) {
FenwickTree fw = new FenwickTree(A.length);
for (int i = 0; i < A.length; i++) {
fw.addValue(i + 1, A[i]);
}
return fw;
}
@Test
public void testGetValue() {
int n = 2000;
long[] A = randomArray(n);
FenwickTree fw = fenwickTree(A);
for (int i = 0; i < A.length; i++) {
assertEquals(A[i], fw.getValue(i + 1));
}
}
@Test
public void testGetMax() {
int n = 500;
long[] A = randomArray(n);
FenwickTree fw = fenwickTree(A);
for (int i = 0; i < A.length; i++) {
assertEquals(getMax(A, i), fw.getMax(i + 1));
}
}
@Test
public void testGetSum() {
int n = 2000;
long[] A = randomArray(n);
FenwickTree fw = fenwickTree(A);
for (int i = 0, cumul = 0; i < A.length; i++) {
cumul += A[i];
assertEquals(cumul, fw.getSum(i + 1));
}
}
@Test
public void testAddValue() {
int n = 2000;
FenwickTree fw = new FenwickTree(n);
long[] A = randomArray(n);
for (int i = 0; i < A.length; i++) {
fw.addValue(i + 1, A[i]);
}
long[] B = fw.toArray();
assertArrayEquals(A, B);
}
@Test
public void testGetRangeSum() {
int n = 500;
long[] A = randomArray(n);
FenwickTree fw = fenwickTree(A);
for (int i = 0; i < A.length; i++) {
for (int j = i; j < A.length; j++) {
long sum = rangeSum(A, i, j);
assertEquals(sum, fw.getRangeSum(i + 1, j + 1));
}
}
}
@Test
public void testFindHigherValueIndex() {
int n = 500;
long[] A = randomArray(n);
FenwickTree fw = fenwickTree(A);
for (int i = 0; i < A.length; i++) {
long sum = fw.getSum(i + 1);
assertEquals(findHigherSumIndex(A, sum) + 1, fw.findHigherSumIndex(sum));
}
long sum = 10000000;
assertEquals(findHigherSumIndex(A, sum) + 1, fw.findHigherSumIndex(sum));
sum = -10000000;
assertEquals(findHigherSumIndex(A, sum) + 1, fw.findHigherSumIndex(sum));
}
@Test
public void testAddValueToRange() {
int n = 500;
long[] A = randomArray(n);
FenwickTree fw = fenwickTree(A);
for (int i = 0; i < A.length; i++) {
for (int j = i; j < A.length; j++) {
long value = random.nextInt(100);
addValueToRange(A, i, j, value);
fw.addValueToRange(i + 1, j + 1, value);
}
}
long[] B = fw.toArray();
assertArrayEquals(A, B);
}
private void testRangeSum() {
long actualSum = 0;
long expSum = 0;
for (int i = 0; i < nums.length; i++) {
expSum = 0;
for (int j = i; j < nums.length; j++) {
expSum += nums[j];
actualSum = testClass.getSum(i, j);
if (expSum != actualSum) {
fail("problem for sum from -->" + i + " to -->" + j);
}
}
}
}
