Problem:
Score : 300 points

Problem Statement

You are given a string S of length N consisting of A, C, G and T. Answer the following Q queries:

Query i (1 \leq i \leq Q): You will be given integers l_i and r_i (1 \leq l_i < r_i \leq N). Consider the substring of S starting at index l_i and ending at index r_i (both inclusive). In this string, how many times does AC occurs as a substring?

Notes

A substring of a string T is a string obtained by removing zero or more characters from the beginning and the end of T.

For example, the substrings of ATCODER include TCO, AT, CODER, ATCODER and (the empty string), but not AC.

Constraints

2 \leq N \leq 10^5

1 \leq Q \leq 10^5

S is a string of length N.

Each character in S is A, C, G or T.

1 \leq l_i < r_i \leq N

Input

Input is given from Standard Input in the following format:

N Q
S
l_1 r_1
:
l_Q r_Q

Output

Print Q lines. The i-th line should contain the answer to the i-th query.

Sample Input 1

8 3
ACACTACG
3 7
2 3
1 8

Sample Output 1

2
0
3

Query 1: the substring of S starting at index 3 and ending at index 7 is ACTAC. In this string, AC occurs twice as a substring.

Query 2: the substring of S starting at index 2 and ending at index 3 is CA. In this string, AC occurs zero times as a substring.

Query 3: the substring of S starting at index 1 and ending at index 8 is ACACTACG. In this string, AC occurs three times as a substring.

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)


import java.util.*;
import java.io.*;

public class Main {

    private static FastScanner sc = new FastScanner();
    private static Solution solution = new Solution();

    private static int[][] neg8 = new int[][]{{-1, -1}, {0, -1}, {1, -1}, {-1, 0}, {1, 0}, {-1, 1}, {0, 1}, {1, 1}};
    private static int[][] neg4 = new int[][]{{1, 0}, {0, -1}, {-1, 0}, {0, 1}};
    /*  neg4    neg8
     *    3      678
     *   2*0     4*5
     *    1      123
     */
    public static void main(String[] args) {

        char[] acgt = {'A','G','T','C'};

        int n = sc.nextInt();
        int q = sc.nextInt();

        String s = sc.next();

        int[][] memo = new int[n][2];

        boolean flag = false;
        int count = 0;

        for(int i = 0;i < n;i++){
                if(i != 0) {
                    memo[i][0] = memo[i - 1][0];
                }
                if(flag && s.charAt(i) == 'C'){
                    count++;
                    memo[i][0]++;
                    memo[i][1]++;
                }
                flag = false;
                if(s.charAt(i)=='A'){
                    flag = true;
                }

        }

        for(int i = 0;i < n;i++){
            System.out.print(memo[i][0] +" ");
        }
        System.out.println();

        for(int i = 0;i < n;i++){
            System.out.print(memo[i][1] +" ");
        }

        for(int i = 0;i < q;i++){
            int start = sc.nextInt() -1;
            int end = sc.nextInt()-1;

            System.out.println(memo[end][0] - memo[start][0] );
        }

    }
}

class Solution {
    public String stringLCS(String s1,String s2){//最長部分文字列そのものを返す
        int l1 = s1.length();//s1の長さ
        int l2 = s2.length();//s2の長さ
        StringBuilder ans = new StringBuilder();
        int last = 0;
        if(l1==0||l2==0){
            return ans.toString();
        }

        int[][] m = new int[l1][l2];
        int maxLen = 0;

        for(int i = 0;i < l1;i++){
            if(s1.charAt(i)==s2.charAt(0)){
                m[i][0] = 1;
                maxLen = 1;
            }else{
                m[i][0] = 0;
            }
        }

        for(int i = 0;i < l2;i++){
            if(s1.charAt(0)==s2.charAt(i)){
                m[0][i] = 1;
                maxLen = 1;
                last = i;
            }else{
                m[0][i] = 0;
            }
        }

        for(int i = 1;i < l1;i ++){
            for(int j = 1;j < l2;j ++){
                if(s1.charAt(i)!=s2.charAt(j)){
                    m[i][j] = 0;
                }else{
                    m[i][j] = m[i-1][j-1] + 1;
                    if(m[i][j] > maxLen){
                        maxLen = m[i][j];
                        last = i;
                    }
                }
            }
        }

        for(int i = last - maxLen +1;i <= last;i++){
            ans.append(String.valueOf(s1.charAt(i)));
        }

        return ans.toString();

    }
    public int countLCS(String s1,String s2){//最長共通部分文字列 文字数を返す
        int l1 = s1.length();//s1の長さ
        int l2 = s2.length();//s2の長さ
        if(l1==0||l2==0){
            return 0;
        }

        int[][] m = new int[l1][l2];
        int maxLen = 0;

        for(int i = 0;i < l1;i++){
            if(s1.charAt(i)==s2.charAt(0)){
                m[i][0] = 1;
                maxLen = 1;
            }else{
                m[i][0] = 0;
            }
        }

        for(int i = 0;i < l2;i++){
            if(s1.charAt(0)==s2.charAt(i)){
                m[0][i] = 1;
                maxLen = 1;
            }else{
                m[0][i] = 0;
            }
        }

        for(int i = 1;i < l1;i ++){
            for(int j = 1;j < l2;j ++){
                if(s1.charAt(i)!=s2.charAt(j)){
                    m[i][j] = 0;
                }else{
                    m[i][j] = m[i-1][j-1] + 1;
                    maxLen = m[i][j] > maxLen?m[i][j]:maxLen;
                }
            }
        }
        return maxLen;


    }

    public List<Integer> prime_factorization(int n){//素数のリストを返す　例：n=12...2,2,3
        final List<Integer> list = new ArrayList<Integer>();
        if(n < 2){
            return list;
        }

        while(n!=1&&n%2==0){
            list.add(2);
            n >>>= 1;
        }

        for(int i = 3;i*i<n;i+=2){
            while(n%i==0){
                list.add(i);
                n/=i;
            }
        }
        if(n!=1){
            list.add(n);
        }
        return list;
    }

    public int count_divisor(int n) {//約数の数を返す
        final List<Integer> list = new ArrayList<Integer>();
        int count = 1;
        int temp;
        if (n < 2) {
            return count;
        }

        temp = 0;
        while (n != 1 && n % 2 == 0) {
            temp++;
            n >>>= 1;
        }
        count *= temp + 1;


        for (int i = 3; i * i < n; i += 2) {
            temp = 0;
            while (n % i == 0) {
                temp++;
                n /= i;
            }
            count *= temp + 1;
        }
        if (n != 1) {
            count*=2;
        }
        return count;
    }
}

class FastScanner extends PrintWriter {
    private final InputStream in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;
    FastScanner() {
        this(System.in);
    }

    FastScanner(InputStream source) {
        super(System.out);
        this.in = source;
    }

    boolean hasNextByte() {
        if (ptr < buflen) {
            return true;
        } else {
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        }
        return true;
    }

    int readByte() {
        if (hasNextByte()) return buffer[ptr++];
        else return -1;
    }

    boolean isPrintableChar(int c) {
        return 33 <= c && c <= 126;
    }

    boolean isNewLine(int c) {
        return c == '\n' || c == '\r';
    }

    void skipUnprintable() {
        while (hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;
    }

    void skipNewLine() {
        while (hasNextByte() && isNewLine(buffer[ptr])) ptr++;
    }

    boolean hasNext() {
        skipUnprintable();
        return hasNextByte();
    }

    boolean hasNextLine() {
        skipNewLine();
        return hasNextByte();
    }

    String next() {
        if (!hasNext()) {
            throw new NoSuchElementException();
        }
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while (isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }

    char[] nextCharArray(int len) {
        if (!hasNext()) {
            throw new NoSuchElementException();
        }
        char[] s = new char[len];
        int i = 0;
        int b = readByte();
        while (isPrintableChar(b)) {
            if (i == len) {
                throw new InputMismatchException();
            }
            s[i++] = (char) b;
            b = readByte();
        }
        return s;
    }

    String nextLine() {
        if (!hasNextLine()) {
            throw new NoSuchElementException();
        }
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while (!isNewLine(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }

    long nextLong() {
        if (!hasNext()) {
            throw new NoSuchElementException();
        }
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if (b == '-') {
            minus = true;
            b = readByte();
        }
        if (b < '0' || '9' < b) {
            throw new NumberFormatException();
        }
        while (true) {
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            } else if (b == -1 || !isPrintableChar(b)) {
                return minus ? -n : n;
            } else {
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }

    int nextInt() {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) {
            throw new NumberFormatException();
        }
        return (int) nl;
    }

    char nextChar() {
        if (!hasNext()) {
            throw new NoSuchElementException();
        }
        return (char) readByte();
    }

    double nextDouble() {
        return Double.parseDouble(next());
    }

    int[] arrayInt(int n) {
        int[] a = new int[n];
        for (int i = 0; i < n; i++) a[i] = nextInt();
        return a;
    }

    long[] arrayLong(int n) {
        long[] a = new long[n];
        for (int i = 0; i < n; i++) a[i] = nextLong();
        return a;
    }

    double[] arrayDouble(int n) {
        double[] a = new double[n];
        for (int i = 0; i < n; i++) a[i] = nextDouble();
        return a;
    }

    void arrayInt(int[]... a) {
        for (int i = 0; i < a[0].length; i++) for (int j = 0; j < a.length; j++) a[j][i] = nextInt();
    }

    int[][] matrixInt(int n, int m) {
        int[][] a = new int[n][];
        for (int i = 0; i < n; i++) a[i] = arrayInt(m);
        return a;
    }

    char[][] mapChar(int n, int m) {
        char[][] a = new char[n][];
        for (int i = 0; i < n; i++) a[i] = nextCharArray(m);
        return a;
    }

    public void close() {
        super.close();
        try {
            in.close();
        } catch (IOException ignored) {
        }
    }
}