Prefix Sums - GenomicRangeQuery

Here is another codility problem solution from the codility lessons (GenomicRangeQuery-Find the minimal nucleotide from a range of sequence DNA..) due to the copy rights I can't copy the content of the problem here so to view the problem description click here.

// you can also use imports, for example:
import java.util.*;

// you can use System.out.println for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
	HashMap < Integer, Integer > ListOfA = new HashMap < Integer, Integer > ();
	HashMap < Integer, Integer > ListOfC = new HashMap < Integer, Integer > ();
	HashMap < Integer, Integer > ListOfG = new HashMap < Integer, Integer > ();
	HashMap < Integer, Integer > ListOfT = new HashMap < Integer, Integer > ();
	public int[] solution(String S, int[] P, int[] Q) {
		// write your code in Java SE 8
		int sum = getSum(S);
		fillMap(S);
		int[] queries = new int[P.length];
		for (int i = 0; i < P.length; i++) {
			int startIndex = P[i];
			int endIndex = Q[i];
			int sumA = ListOfA.get(endIndex) - ListOfA.get(startIndex);

			if (S.charAt(startIndex) == 'A') sumA++;

			if (sumA > 0) {
				queries[i] = 1;
			} else {
				int sumC = ListOfC.get(endIndex) - ListOfC.get(startIndex);
				if (S.charAt(startIndex) == 'C') sumC++;

				if (sumC > 0) {
					queries[i] = 2;
				} else {
					int sumG = ListOfG.get(endIndex) - ListOfG.get(startIndex);
					if (S.charAt(startIndex) == 'G') sumG++;

					if (sumG > 0) {
						queries[i] = 3;
					} else {
						int sumT = ListOfT.get(endIndex) - ListOfT.get(startIndex);
						if (S.charAt(startIndex) == 'T') sumT++;

						if (sumT > 0) {
							queries[i] = 4;
						}
					}
				}
			}

			// System.out.println(queries[i]+"========"+P[i]+"========"+Q[i]);
		}

		// System.out.println(S);

		return queries;
	}

	private void fillMap(String S) {
		int sumA = 0;
		int sumC = 0;
		int sumG = 0;
		int sumT = 0;
		int len = S.length();
		for (int i = 0; i < len; i++) {
			char c = S.charAt(i);
			switch (c) {
				case 'A':
					sumA++;
					break;
				case 'C':
					sumC++;
					break;
				case 'G':
					sumG++;
					break;
				case 'T':
					sumT++;
					break;

			}
			ListOfA.put(i, sumA);
			ListOfC.put(i, sumC);
			ListOfG.put(i, sumG);
			ListOfT.put(i, sumT);


		}

	}
	private int getSum(String S) {
		int sum = 0;
		int len = S.length();
		for (int i = 0; i < len; i++) {
			sum += mapChartoInt(S.charAt(i));
		}
		return sum;

	}
	private int mapChartoInt(char c) {
		int mappedVal = -1;
		switch (c) {
			case 'A':
				mappedVal = 1;
				break;
			case 'C':
				mappedVal = 2;
				break;
			case 'G':
				mappedVal = 3;
				break;
			case 'T':
				mappedVal = 4;
				break;

		}
		return mappedVal;
	}
}

Prefix Sums - PassingCars

Here is another codility problem solution from the codility lessons (PassingCars-Count the number of passing cars on the road.) due to the copy rights I can't copy the content of the problem here so to view the problem description click here.

class Solution {
	public int solution(int[] A) {
		// write your code in Java SE 8
		boolean isZero = false;
		int zeroCount = 0;
		int pairCount = 0;

		for (int i = 0; i < A.length; i++) {
			if (A[i] == 0) {
				isZero = true;
				zeroCount++;
			} else if (A[i] == 1) {
				if (isZero) {
					pairCount = pairCount + zeroCount;
					if (pairCount > 1000000000) return -1;
				} else {
					continue;
				}
			}

		}


		return pairCount;
	}
}

Prefix Sums-CountDiv

Here is another codility problem solution from the codility lessons (CountDiv-Compute number of integers divisible by k in range [a..b].) due to the copy rights I can't copy the content of the problem here so to view the problem description click here.

class Solution {
	public int solution(int A, int B, int K) {
		// write your code in Java SE 8
		int count = 0;
		int div1 = 0;
		int div2 = 0;

		div1 = A / K;
		div2 = B / K;
		count = div2 - div1;
		if (A % K == 0) count++;

		return count;
	}
}

Prefix Sums - MinAvgTwoSlice

Here is another codility problem solution from the codility lessons (MinAvgTwoSlice-Find the minimal average of any slice containing at least two elements.) due to the copy rights I can't copy the content of the problem here so to view the problem description click here.

class Solution {
	public int solution(int[] A) {
		long min = Long.MAX_VALUE;
		int index = -1;
		//we have A+B/2 to be comapred with A+B+C/3
		//to make things easiler we are going to multuply both side with 6


		for (int i = 0; i < A.length - 2; i++) {

			long res1 = ((A[i] + A[i + 1])) * 3;
			long res2 = ((A[i] + A[i + 1] + A[i + 2])) * 2;



			long minRes = Math.min(res1, res2);

			if (minRes < min) {
				min = minRes;
				index = i;
			}

		}
		if ((A[A.length - 2] + A[A.length - 1]) * 3 < min) {
			return A.length - 2;
		}

		return index;
	}
}

Stacks and Queues - Fish

Here is another codility problem solution from the codility lessons (Fish-N voracious fish are moving along a river. Calculate how many fish are alive.) due to the copy rights I can't copy the content of the problem here so to view the problem description click here.

// you can also use imports, for example:
import java.util.*;

// you can use System.out.println for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
	public int solution(int[] A, int[] B) {

		int count = 0;
		Stack < Integer > previousFishes = new Stack < Integer > ();

		for (int i = 0; i < A.length; i++) {
			int currentFish = A[i];
			int currentFlow = B[i];
			if (currentFlow == 1) {
				previousFishes.push(currentFish);
			}
			if (!previousFishes.empty() && currentFlow == 0) {
				while (!previousFishes.empty() && currentFish > previousFishes.peek()) {
					int fish = previousFishes.pop();
				}
			}
			if (previousFishes.empty() && currentFlow == 0) {
				count++;
			}

		}
		return count + previousFishes.size();
	}
}

Stacks and Queues - Nesting

Here is another codility problem solution from the codility lessons (Nesting -Determine whether given string of parentheses is properly nested.) due to the copy rights I can't copy the content of the problem here so to view the problem description click here.

// you can also use imports, for example:
import java.util.*;

// you can use System.out.println for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
	public int solution(String S) {
		// write your code in Java SE 8
		if (S.length() % 2 != 0) return 0;
		if (S.length() == 0) return 1;



		Stack < Character > st = new Stack < Character > ();
		for (int i = 0; i < S.length(); i++) {

			if (isOpenTag(S.charAt(i))) {
				st.add(S.charAt(i));
			} else {
				if (!st.empty()) {
					char sc = st.pop();
					if (getCloseTag(sc) != S.charAt(i)) return 0;
				} else {
					return 0;
				}
			}

		}
		if (!st.empty()) return 0;

		return 1;


	}

	private char getCloseTag(char c) {
		switch (c) {
			case ('('):
				return ')';
			default:
				return ' ';

		}
	}

	private boolean isOpenTag(char c) {
		switch (c) {
			case ('('):
				return true;


			default:
				return false;

		}
	}

}