findKthSmallestNumber.java Linear

    private static int findKthSmallestNumber3(int[] data, int low, int high, int k) {
        if (k > 0 && k <=  high - low + 1) {
            int partitionCalculated = partition(data, low, high);

            if (partitionCalculated - 1 == k -1 ) {
                return data[partitionCalculated - 1 ];
            }

            if (partitionCalculated - 1 > k -1) {
                return findKthSmallestNumber3(data, low, partitionCalculated - 1, k);
            }

            return findKthSmallestNumber3(data, partitionCalculated + 1, high, k - partitionCalculated + low - 1);
        }
        return Integer.MAX_VALUE;
    }

findKthSmallestNumber.java Quadratic

    private static int findKthSmallestNumber(int[] numbers, int k) {
        int[] acums = new int[numbers.length];
        int length = numbers.length;
        for (int i = 0; i < length; i++) {
            for(int j= i + 1; j < length; j++) {
                if (numbers[i] >= numbers[j]) {
                    acums[i] = acums[i] + 1;
                }
                else {
                    acums[j] = acums[j] + 1;
                }
            }
            if (acums[i] == k - 1) {
                return numbers[i];
            }
        }
        return Integer.MAX_VALUE;
    }