Anagram Index Finder — Problem Statement & Solution Guide

#include <bits/stdc++.h>
using namespace std;
vector<int> findAnagramIndices(const string& s, const string& p){
    int n=s.size(), m=p.size();
    if(m==0||n<m) return {};
    const int ALPH=256;
    int need[ALPH] = {0}, have[ALPH] = {0};
    for(char c: p) need[(unsigned char)c]++;
    int diff=0; // number of chars where have!=need
    for(int i=0;i<ALPH;i++) if(need[i]!=0) diff++;
    vector<int> res;
    for(int i=0;i<n;i++){
        unsigned char in=s[i];
        have[in]++;
        if(have[in]==need[in]) diff--; else if(have[in]==need[in]+1) diff++;
        if(i>=m){
            unsigned char out=s[i-m];
            if(have[out]==need[out]) diff++; else if(have[out]==need[out]+1) diff--;
            have[out]--;
        }
        if(i>=m-1 && diff==0) res.push_back(i-m+1);
    }
    return res;
}
int main(){ios::sync_with_stdio(false);cin.tie(nullptr);string seq, pat; if(!(cin>>seq>>pat)) return 0;auto ans=findAnagramIndices(seq,pat); for(size_t i=0;i<ans.size();++i){if(i) cout<<' ';cout<<ans[i];}cout<<"\n";}

import java.io.*;
import java.util.*;
public class Main {
    static List<Integer> findAnagramIndices(String s, String p){
        int n=s.length(), m=p.length();
        if(m==0||n<m) return new ArrayList<>();
        final int ALPH=256;
        int[] need=new int[ALPH];
        int[] have=new int[ALPH];
        for(int i=0;i<m;i++) need[p.charAt(i)]++;
        int diff=0;
        for(int i=0;i<ALPH;i++) if(need[i]!=0) diff++;
        List<Integer> res=new ArrayList<>();
        for(int i=0;i<n;i++){
            int in=s.charAt(i);
            have[in]++;
            if(have[in]==need[in]) diff--; else if(have[in]==need[in]+1) diff++;
            if(i>=m){
                int out=s.charAt(i-m);
                if(have[out]==need[out]) diff++; else if(have[out]==need[out]+1) diff--;
                have[out]--;
            }
            if(i>=m-1 && diff==0) res.add(i-m+1);
        }
        return res;
    }
    public static void main(String[] args) throws Exception {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        String line=br.readLine();
        if(line==null) return;
        StringTokenizer st=new StringTokenizer(line);
        String seq=st.nextToken();
        String pat=st.nextToken();
        List<Integer> ans=findAnagramIndices(seq,pat);
        for(int i=0;i<ans.size();i++){
            if(i>0) System.out.print(" ");
            System.out.print(ans.get(i));
        }
        System.out.println();
    }
}

import sys
def find_anagram_indices(s: str, p: str):
    n, m = len(s), len(p)
    if m == 0 or n < m:
        return []
    ALPH = 256
    need = [0]*ALPH
    have = [0]*ALPH
    for ch in p:
        need[ord(ch)] += 1
    diff = sum(1 for cnt in need if cnt != 0)
    res = []
    for i in range(n):
        inc = ord(s[i])
        have[inc] += 1
        if have[inc] == need[inc]:
            diff -= 1
        elif have[inc] == need[inc] + 1:
            diff += 1
        if i >= m:
            outc = ord(s[i-m])
            if have[outc] == need[outc]:
                diff += 1
            elif have[outc] == need[outc] + 1:
                diff -= 1
            have[outc] -= 1
        if i >= m-1 and diff == 0:
            res.append(i-m+1)
    return res
if __name__ == "__main__":
    data = sys.stdin.read().strip().split()
    if len(data) >= 2:
        seq, pat = data[0], data[1]
        ans = find_anagram_indices(seq, pat)
        print(' '.join(map(str, ans)))

const fs = require('fs');
const input = fs.readFileSync(0,'utf8').trim().split(/\s+/);
function findAnagramIndices(sequence, pattern){
    const n = sequence.length, m = pattern.length;
    if(m===0 || n<m) return [];
    const ALPH = 256;
    const need = new Array(ALPH).fill(0);
    const have = new Array(ALPH).fill(0);
    for(let i=0;i<m;i++) need[pattern.charCodeAt(i)]++;
    let diff = 0;
    for(let i=0;i<ALPH;i++) if(need[i]!==0) diff++;
    const res = [];
    for(let i=0;i<n;i++){
        const inChar = sequence.charCodeAt(i);
        have[inChar]++;
        if(have[inChar]===need[inChar]) diff--; else if(have[inChar]===need[inChar]+1) diff++;
        if(i>=m){
            const outChar = sequence.charCodeAt(i-m);
            if(have[outChar]===need[outChar]) diff++; else if(have[outChar]===need[outChar]+1) diff--;
            have[outChar]--;
        }
        if(i>=m-1 && diff===0) res.push(i-m+1);
    }
    return res;
}
if(input.length>=2){
    const seq = input[0];
    const pat = input[1];
    const ans = findAnagramIndices(seq, pat);
    console.log(ans.join(' '));
}