GenomicRangeQuery

A DNA sequence can be represented as a string consisting of the letters A, C, G and T, which correspond to the types of successive nucleotides in the sequence. Each nucleotide has an impact factor, which is an integer. Nucleotides of types A, C, G and T have impact factors of 1, 2, 3 and 4, respectively. You are going to answer several queries of the form: What is the minimal impact factor of nucleotides contained in a particular part of the given DNA sequence?

The DNA sequence is given as a non-empty string S = S[0]S[1]...S[N-1] consisting of N characters. There are M queries, which are given in non-empty arrays P and Q, each consisting of M integers. The K-th query (0 ≤ K < M) requires you to find the minimal impact factor of nucleotides contained in the DNA sequence between positions P[K] and Q[K] (inclusive).

For example, consider string S = CAGCCTA and arrays P, Q such that:

P[0] = 2 Q[0] = 4 P[1] = 5 Q[1] = 5 P[2] = 0 Q[2] = 6

The answers to these M = 3 queries are as follows:

• The part of the DNA between positions 2 and 4 contains nucleotides G and C (twice), whose impact factors are 3 and 2 respectively, so the answer is 2.
• The part between positions 5 and 5 contains a single nucleotide T, whose impact factor is 4, so the answer is 4.
• The part between positions 0 and 6 (the whole string) contains all nucleotides, in particular nucleotide A whose impact factor is 1, so the answer is 1.

Write a function:

class Solution { public int[] solution(String S, int[] P, int[] Q); }

that, given a non-empty string S consisting of N characters and two non-empty arrays P and Q consisting of M integers, returns an array consisting of M integers specifying the consecutive answers to all queries.

Result array should be returned as an array of integers.

For example, given the string S = CAGCCTA and arrays P, Q such that:

P[0] = 2 Q[0] = 4 P[1] = 5 Q[1] = 5 P[2] = 0 Q[2] = 6

the function should return the values [2, 4, 1], as explained above.

Write an efficient algorithm for the following assumptions:

• N is an integer within the range [1..100,000];
• M is an integer within the range [1..50,000];
• each element of arrays P, Q is an integer within the range [0..N − 1];
• P[K] ≤ Q[K], where 0 ≤ K < M;
• string S consists only of upper-case English letters A, C, G, T.
  
  

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

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

class Solution {
    public int[] solution(String S, int[] P, int[] Q) {
        // write your code in Java SE 8
        int length = S.length();
        int []results = new int[P.length];
        int impactLength = 4; //글자별 점수?
        
        int[] impactCnt = new int[impactLength]; //글자별 누적합 저장
        int[][] impactFactorArray = new int[impactLength][length+1]; // 1,2,3,4 가 S ~까지 몇개 인지 나타냄
		
        int impactFactor =0;
       
       for(int i=0; i<S.length(); i++){
           char ch = S.charAt(i);
           if(ch=='A'){
               impactFactor =1;
           }
           else if(ch=='C'){
              impactFactor =2;
           }
           else if(ch=='G'){
              impactFactor =3;
           }
           else if(ch =='T'){
               impactFactor =4;
           }
            impactCnt[impactFactor-1]++; 
           for(int j=0; j<4; j++){
               impactFactorArray[j][i+1]= impactCnt[j];//문자열의 i+1번째까지1~4 의 누적개수를 저장
           }

       }

       for(int i=0; i<P.length; i++){
           for(int j=0; j<impactLength; j++){
           
        if(impactFactorArray[j][Q[i]+1] - impactFactorArray[j][P[i]]>0){//누적한 것들을 뻈을 때
            results[i]=j+1;
            break;
        }

           }
       }
        return results;
    }
}