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Here is my solution in java, C++ HackerRank Definite Random Walks Solution

Here is the solution of Definite Random Walks Click Here

Here is problem solution - https://programs.programmingoneonone.com/2021/07/hackerrank-definite-random-walks-problem-solution.html

import java.io.ByteArrayInputStream; import java.io.IOException; import java.io.InputStream; import java.io.PrintWriter; import java.util.Arrays; import java.util.HashMap; import java.util.InputMismatchException; import java.util.Map;

public class G2 { InputStream is; PrintWriter out; String INPUT = ""; // String INPUT = "7 3 1\r\n" + // "4 2 7 2 4 3 5 \r\n" + // "0 1 0 "; // String INPUT = "4 2 1\r\n" + // "1 4 2 3 \r\n" + // "748683265 249561089"; // 1 2->4->3->2 // String INPUT = "4 2 2\r\n" + // "2 3 1 3 \r\n" + // "0 1 "; // 1/4 1/4 1/2 // 1/2 1/4 1/4 // String INPUT = "3 1 2\r\n" + // "1 3 1 \r\n" + // "1 "; // String INPUT = "4 5 1\r\n" + // "2 3 2 4\r\n" + // "332748118 332748118 332748118 0 0";

void solve()
{
    int n = ni(), m = ni(), K = ni();
    int[] f = na(n);
    for(int i = 0;i < n;i++)f[i]--;
    long[] ps = new long[m];
    for(int i = 0;i < m;i++)ps[i] = nl();
    int mod = 998244353;

// tr("phase 0"); long[] made = make(ps, K, n+1, 1);

    int H = (int)Math.sqrt(n)*8; // naive height limit
    int B = (int)Math.sqrt(n)*8; // cycle split period

    SplitResult sres = split(f);
    int[] tclus = new int[n];
    Arrays.fill(tclus, -1);
    for(int i = n-1;i >= 0;i--){
        int cur = sres.ord[i];
        if(sres.incycle[cur]){
            tclus[cur] = cur;
        }else{
            tclus[cur] = tclus[f[cur]];
        }
    }

// tr("phase 1"); long[] rets = new long[n]; int[][] maps = makeBuckets(tclus, n); for(int i = 0;i < n;i++){ if(maps[i].length > 0){ int[] map = maps[i]; int[] lpar = new int[map.length]; int p = 0; for(int x : maps[i]){ if(sres.incycle[x]){ lpar[p++] = -1; }else{ lpar[p++] = Arrays.binarySearch(map, f[x]); } } long[] res = solve(parentToG(lpar), lpar, made, H, Arrays.binarySearch(map, i)); for(int j = 0;j < res.length;j++){ if(!sres.incycle[map[j]]){ rets[map[j]] += res[j]; } } } } // tr("phase 2");

    int[] maxdep = new int[n];
    for(int i = 0;i < n;i++){
        int cur = sres.ord[i];
        if(!sres.incycle[cur]){
            maxdep[f[cur]] = Math.max(maxdep[f[cur]], maxdep[cur]+1);
        }
    }
    int[] tdep = new int[n];
    for(int i = n-1;i >= 0;i--){
        int cur = sres.ord[i];
        if(!sres.incycle[cur]){
            tdep[cur] = tdep[f[cur]]+1;
        }
    }

// tr("phase 3"); // for(int j = made.length-1-1;j >= 0;j--){ // made[j] += made[j+1]; // if(made[j] >= mod)made[j] -= mod; // }

    boolean[] ved = new boolean[n];
    int[] cycle = new int[n];
    Map<Long, long[]> cache = new HashMap<>();
    for(int i = 0;i < n;i++){
        if(sres.incycle[i] && !ved[i]){
            int p = 0;
            ved[i] = true;
            cycle[p++] = i;
            int lmaxdep = maxdep[i];
            for(int j = f[i];!ved[j];j = f[j]){
                ved[j] = true;
                cycle[p++] = j;
                lmaxdep = Math.max(lmaxdep, maxdep[j]);
            }
            int tail = lmaxdep+p+1;
            int fp = p;
            long[] di = cache.computeIfAbsent((long)tail<<32|fp, (z) -> {
                long[] res = make(ps, K, tail, fp);
                for(int j = res.length-fp-1;j >= 0;j--){
                    res[j] += res[j+fp];
                    if(res[j] >= mod)res[j] -= mod;
                }
                return res;
            });
            // 0.1 0.2 0.3 0.4
            // 0.4 0.6
            // 0.1 0.6 0.3
            // 0.1 0.2 0.3 0.4

            // 0.4 0.6
            // 0.6 0.3
            // 0.3 0.4


            if(p <= B){
                for(int j = 0;j < p;j++){
                    for(int v : maps[cycle[j]]){
                        for(int k = tdep[v], l = j;k < tdep[v]+p;k++,l++){
                            if(l == p)l = 0;
                            rets[cycle[l]] += di[k];
                        }
                    }
                }
            }else{
                inputed = null;
                for(int b = 0;b < p;b+=B){
                    long[] ents = new long[tail+1];
                    for(int j = 0;j < b;j++){
                        for(int v : maps[cycle[j]]){
                            ents[tail-(b-j)-tdep[v]]++;
                        }
                    }
                    for(int j = b+B;j < p;j++){
                        for(int v : maps[cycle[j]]){
                            ents[tail-b-(p-j)-tdep[v]]++;
                        }
                    }
                    long[] ced = convoluteSimply(ents, di, mod, 3);
                    inputed = saved;
                    for(int k = b;k < p && k < b+B;k++){
                        rets[cycle[k]] += ced[tail+k-b];
                    }
                }
                inputed = null;

                // remainder
                for(int j = 0;j < p;j++){
                    for(int v : maps[cycle[j]]){
                        for(int k = tdep[v], l = j;k < tdep[v]+p && l < p && l < j/B*B+B;k++,l++){
                            rets[cycle[l]] += di[k];
                        }
                        for(int k = tdep[v]+p-j+j/B*B, l = j/B*B;k < tdep[v]+p && l < j;k++,l++){
                            rets[cycle[l]] += di[k];
                        }
                    }
                }
            }
        }
    }

// tr("phase 4");

    long RN = invl(n, mod);
    for(long ret : rets){
        out.println(ret%mod*RN%mod);
    }
}

int mod = 998244353;

long[] make(long[] ps, int K, int tail, int period)
{
    long[] ms = ps;
    if(ps.length > tail+period){
        ms = Arrays.copyOf(ps, tail+period);
        for(int j = tail+period, k = tail;j < ps.length;j++,k++){
            if(k == tail+period)k -= period;
            ms[k] += ps[j];
            if(ms[k] >= mod)ms[k] -= mod;
        }
    }

    long[] pps = new long[1];
    pps[0] = 1;
    for(int i = 0;1<<i <= K;i++){
        if(K<<~i<0){
            long[] res = convoluteSimply(pps, ms, mod, 3);
            for(int j = res.length-1-period;j >= tail;j--){
                res[j] += res[j+period];
                res[j+period] = 0;
                if(res[j] >= mod)res[j] -= mod;
            }
            pps = Arrays.copyOf(res, Math.min(tail+period, pps.length+ms.length));
        }

        if(1<<i+1 <= K){
            long[] res = convoluteSimply(ms, ms, mod, 3);
            for(int j = res.length-1-period;j >= tail;j--){
                res[j] += res[j+period];
                res[j+period] = 0;
                if(res[j] >= mod)res[j] -= mod;
            }
            ms = Arrays.copyOf(res, Math.min(tail+period, ms.length+ms.length));
        }
    }
    if(pps.length < tail+period)pps = Arrays.copyOf(pps, tail+period);
    return pps;
}

long[] solve(int[][] g, int[] par, long[] di, int H, int root)
{
    int n = g.length;
    long[] ret = new long[n];
    int[][] pars = parents3(g, root);
    int[] des = new int[n];
    long[] ws = new long[n];
    int[] ord = pars[1], dep = pars[2];
    int[] marked = new int[n];
    for(int i = n-1;i >= 0;i--){
        int cur = ord[i];
        des[cur]++;
        ws[cur] += des[cur];
        if(marked[cur] == 0 && ws[cur] > (long)H*des[cur]){
            marked[cur] = 1;
        }
        if(i > 0){
            des[par[cur]] += des[cur];
            ws[par[cur]] += ws[cur];
            if(marked[cur] >= 1)marked[par[cur]] = 2;
        }
    }

// tr(g, root); // tr(marked);

    // large
    // marked node
    for(int i = 0;i < n;i++){
        if(marked[i] == 1){
            int[] fdep = new int[n];
            collect(i, par[i], g, dep, fdep);
            for(int j = par[i];j != -1 && marked[j] == 2;j = par[j]){
                fdep[dep[j]]++;
                marked[j] = 3;
            }

            int lmaxdep = n;
            for(int j = n-1;j >= 0;j--){
                if(fdep[j] > 0){
                    lmaxdep = j;
                    break;
                }
            }
            long[] rfdep = new long[lmaxdep+1];
            for(int j = 0;j <= lmaxdep;j++){
                rfdep[lmaxdep-j] = fdep[j];
            }

// tr("fdep", fdep, marked); long[] ced = convoluteSimply(rfdep, Arrays.copyOf(di, lmaxdep+1), mod, 3); for(int j = i;j != -1;j = par[j]){ ret[j] += ced[lmaxdep-dep[j]]; } } }

    // small
    for(int i = 0;i < n;i++){
        if(marked[i] == 0){
            for(int j = i;j != -1 && marked[j] != 1;j = par[j]){
                ret[j] += di[dep[i]-dep[j]];
            }
        }
    }

    for(int i = 0;i < n;i++){
        ret[i] %= mod;
    }

    return ret;
}

void collect(int cur, int par, int[][] g, int[] dep, int[] fdep)
{
    fdep[dep[cur]]++;
    for(int e : g[cur]){
        if(e != par)collect(e, cur, g, dep, fdep);
    }
}

// library

public static int[][] parents3(int[][] g, int root) {
    int n = g.length;
    int[] par = new int[n];
    Arrays.fill(par, -1);

    int[] depth = new int[n];
    depth[0] = 0;

    int[] q = new int[n];
    q[0] = root;
    for (int p = 0, r = 1; p < r; p++) {
        int cur = q[p];
        for (int nex : g[cur]) {
            if (par[cur] != nex) {
                q[r++] = nex;
                par[nex] = cur;
                depth[nex] = depth[cur] + 1;
            }
        }
    }
    return new int[][] { par, q, depth };
}


public static final int[] NTTPrimes = {1053818881, 1051721729, 1045430273, 1012924417, 1007681537, 1004535809, 998244353, 985661441, 976224257, 975175681};
public static final int[] NTTPrimitiveRoots = {7, 6, 3, 5, 3, 3, 3, 3, 3, 17};

// public static final int[] NTTPrimes = {1012924417, 1004535809, 998244353, 985661441, 975175681, 962592769, 950009857, 943718401, 935329793, 924844033}; // public static final int[] NTTPrimitiveRoots = {5, 3, 3, 3, 17, 7, 7, 7, 3, 5};

static long[] inputed;
static long[] saved;

public static long[] convoluteSimply(long[] a, long[] b, int P, int g)
{
    int m = Math.max(2, Integer.highestOneBit(Math.max(a.length, b.length)-1)<<2);
    long[] fa = nttmb(a, m, false, P, g);
    long[] fb = a == b ? fa : inputed != null ? inputed : nttmb(b, m, false, P, g);
    saved = fb;
    for(int i = 0;i < m;i++){
        fa[i] = fa[i]*fb[i]%P;
    }
    return nttmb(fa, m, true, P, g);
}

public static long[] convolute(long[] a, long[] b)
{
    int USE = 2;
    int m = Math.max(2, Integer.highestOneBit(Math.max(a.length, b.length)-1)<<2);
    long[][] fs = new long[USE][];
    for(int k = 0;k < USE;k++){
        int P = NTTPrimes[k], g = NTTPrimitiveRoots[k];
        long[] fa = nttmb(a, m, false, P, g);
        long[] fb = a == b ? fa : nttmb(b, m, false, P, g);
        for(int i = 0;i < m;i++){
            fa[i] = fa[i]*fb[i]%P;
        }
        fs[k] = nttmb(fa, m, true, P, g);
    }

    int[] mods = Arrays.copyOf(NTTPrimes, USE);
    long[] gammas = garnerPrepare(mods);
    int[] buf = new int[USE];
    for(int i = 0;i < fs[0].length;i++){
        for(int j = 0;j < USE;j++)buf[j] = (int)fs[j][i];
        long[] res = garnerBatch(buf, mods, gammas);
        long ret = 0;
        for(int j = res.length-1;j >= 0;j--)ret = ret * mods[j] + res[j];
        fs[0][i] = ret;
    }
    return fs[0];
}

public static long[] convolute(long[] a, long[] b, int USE, int mod)
{
    int m = Math.max(2, Integer.highestOneBit(Math.max(a.length, b.length)-1)<<2);
    long[][] fs = new long[USE][];
    for(int k = 0;k < USE;k++){
        int P = NTTPrimes[k], g = NTTPrimitiveRoots[k];
        long[] fa = nttmb(a, m, false, P, g);
        long[] fb = a == b ? fa : nttmb(b, m, false, P, g);
        for(int i = 0;i < m;i++){
            fa[i] = fa[i]*fb[i]%P;
        }
        fs[k] = nttmb(fa, m, true, P, g);
    }

    int[] mods = Arrays.copyOf(NTTPrimes, USE);
    long[] gammas = garnerPrepare(mods);
    int[] buf = new int[USE];
    for(int i = 0;i < fs[0].length;i++){
        for(int j = 0;j < USE;j++)buf[j] = (int)fs[j][i];
        long[] res = garnerBatch(buf, mods, gammas);
        long ret = 0;
        for(int j = res.length-1;j >= 0;j--)ret = (ret * mods[j] + res[j]) % mod;
        fs[0][i] = ret;
    }
    return fs[0];
}

// static int[] wws = new int[270000]; // outer faster

// Modifed Montgomery + Barrett
private static long[] nttmb(long[] src, int n, boolean inverse, int P, int g)
{
    long[] dst = Arrays.copyOf(src, n);

    int h = Integer.numberOfTrailingZeros(n);
    long K = Integer.highestOneBit(P)<<1;
    int H = Long.numberOfTrailingZeros(K)*2;
    long M = K*K/P;

    int[] wws = new int[1<<h-1];
    long dw = inverse ? pow(g, P-1-(P-1)/n, P) : pow(g, (P-1)/n, P);
    long w = (1L<<32)%P;
    for(int k = 0;k < 1<<h-1;k++){
        wws[k] = (int)w;
        w = modh(w*dw, M, H, P);
    }
    long J = invl(P, 1L<<32);
    for(int i = 0;i < h;i++){
        for(int j = 0;j < 1<<i;j++){
            for(int k = 0, s = j<<h-i, t = s|1<<h-i-1;k < 1<<h-i-1;k++,s++,t++){
                long u = (dst[s] - dst[t] + 2*P)*wws[k];
                dst[s] += dst[t];
                if(dst[s] >= 2*P)dst[s] -= 2*P;

// long Q = (u&(1L<<32)-1)*J&(1L<<32)-1; long Q = (u<<32)*J>>>32; dst[t] = (u>>>32)-(Q*P>>>32)+P; } } if(i < h-1){ for(int k = 0;k < 1<= P)dst[i] -= P; } for(int i = 0;i < n;i++){ int rev = Integer.reverse(i)>>>-h; if(i < rev){ long d = dst[i]; dst[i] = dst[rev]; dst[rev] = d; } }

    if(inverse){
        long in = invl(n, P);
        for(int i = 0;i < n;i++)dst[i] = modh(dst[i]*in, M, H, P);
    }

    return dst;
}

// Modified Shoup + Barrett
private static long[] nttsb(long[] src, int n, boolean inverse, int P, int g)
{
    long[] dst = Arrays.copyOf(src, n);

    int h = Integer.numberOfTrailingZeros(n);
    long K = Integer.highestOneBit(P)<<1;
    int H = Long.numberOfTrailingZeros(K)*2;
    long M = K*K/P;

    long dw = inverse ? pow(g, P-1-(P-1)/n, P) : pow(g, (P-1)/n, P);
    long[] wws = new long[1<<h-1];
    long[] ws = new long[1<<h-1];
    long w = 1;
    for(int k = 0;k < 1<<h-1;k++){
        wws[k] = (w<<32)/P;
        ws[k] = w;
        w = modh(w*dw, M, H, P);
    }
    for(int i = 0;i < h;i++){
        for(int j = 0;j < 1<<i;j++){
            for(int k = 0, s = j<<h-i, t = s|1<<h-i-1;k < 1<<h-i-1;k++,s++,t++){
                long ndsts = dst[s] + dst[t];
                if(ndsts >= 2*P)ndsts -= 2*P;
                long T = dst[s] - dst[t] + 2*P;
                long Q = wws[k]*T>>>32;
                dst[s] = ndsts;
                dst[t] = ws[k]*T-Q*P&(1L<<32)-1;
            }
        }

// dw = dw * dw % P; if(i < h-1){ for(int k = 0;k < 1<= P)dst[i] -= P; } for(int i = 0;i < n;i++){ int rev = Integer.reverse(i)>>>-h; if(i < rev){ long d = dst[i]; dst[i] = dst[rev]; dst[rev] = d; } }

    if(inverse){
        long in = invl(n, P);
        for(int i = 0;i < n;i++){
            dst[i] = modh(dst[i] * in, M, H, P);
        }
    }

    return dst;
}

static final long mask = (1L<<31)-1;

public static long modh(long a, long M, int h, int mod)
{
    long r = a-((M*(a&mask)>>>31)+M*(a>>>31)>>>h-31)*mod;
    return r < mod ? r : r-mod;
}

private static long[] garnerPrepare(int[] m)
{
    int n = m.length;
    assert n == m.length;
    if(n == 0)return new long[0];
    long[] gamma = new long[n];
    for(int k = 1;k < n;k++){
        long prod = 1;
        for(int i = 0;i < k;i++){
            prod = prod * m[i] % m[k];
        }
        gamma[k] = invl(prod, m[k]);
    }
    return gamma;
}

private static long[] garnerBatch(int[] u, int[] m, long[] gamma)
{
    int n = u.length;
    assert n == m.length;
    long[] v = new long[n];
    v[0] = u[0];
    for(int k = 1;k < n;k++){
        long temp = v[k-1];
        for(int j = k-2;j >= 0;j--){
            temp = (temp * m[j] + v[j]) % m[k];
        }
        v[k] = (u[k] - temp) * gamma[k] % m[k];
        if(v[k] < 0)v[k] += m[k];
    }
    return v;
}

private static long pow(long a, long n, long mod) {
    //      a %= mod;
    long ret = 1;
    int x = 63 - Long.numberOfLeadingZeros(n);
    for (; x >= 0; x--) {
        ret = ret * ret % mod;
        if (n << 63 - x < 0)
            ret = ret * a % mod;
    }
    return ret;
}

private static long invl(long a, long mod) {
    long b = mod;
    long p = 1, q = 0;
    while (b > 0) {
        long c = a / b;
        long d;
        d = a;
        a = b;
        b = d % b;
        d = p;
        p = q;
        q = d - c * q;
    }
    return p < 0 ? p + mod : p;
}

public static int[][] parentToG(int[] par)
{
    int n = par.length;
    int[] ct = new int[n];
    for(int i = 0;i < n;i++){
        if(par[i] >= 0){
            ct[i]++;
            ct[par[i]]++;
        }
    }
    int[][] g = new int[n][];
    for(int i = 0;i < n;i++){
        g[i] = new int[ct[i]];
    }
    for(int i = 0;i < n;i++){
        if(par[i] >= 0){
            g[par[i]][--ct[par[i]]] = i;
            g[i][--ct[i]] = par[i];
        }
    }
    return g;
}


public static int[][] makeBuckets(int[] a, int sup)
{
    int n = a.length;
    int[][] bucket = new int[sup+1][];
    int[] bp = new int[sup+1];
    for(int i = 0;i < n;i++)bp[a[i]]++;
    for(int i = 0;i <= sup;i++)bucket[i] = new int[bp[i]];
    for(int i = n-1;i >= 0;i--)bucket[a[i]][--bp[a[i]]] = i;
    return bucket;
}


public static class SplitResult
{
    public boolean[] incycle;
    public int[] ord;
}

public static SplitResult split(int[] f)
{
    int n = f.length;
    boolean[] incycle = new boolean[n];
    Arrays.fill(incycle, true);
    int[] indeg = new int[n];
    for(int i = 0;i < n;i++)indeg[f[i]]++;
    int[] q = new int[n];
    int qp = 0;
    for(int i = 0;i < n;i++){
        if(indeg[i] == 0)q[qp++] = i;
    }
    for(int r = 0;r < qp;r++){
        int cur = q[r];
        indeg[cur] = -9999999;
        incycle[cur] = false;
        int e = f[cur];
        indeg[e]--;
        if(indeg[e] == 0)q[qp++] = e;
    }
    for(int i = 0;i < n;i++){
        if(indeg[i] == 1){
            q[qp++] = i;
        }
    }
    assert qp == n;
    SplitResult ret = new SplitResult();
    ret.incycle = incycle;
    ret.ord = q;
    return ret;
}


void run() throws Exception
{
    is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
    out = new PrintWriter(System.out);

    long s = System.currentTimeMillis();
    solve();
    out.flush();
    if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
}

public static void main(String[] args) throws Exception { new G2().run(); }

private byte[] inbuf = new byte[1024];
public int lenbuf = 0, ptrbuf = 0;

private int readByte()
{
    if(lenbuf == -1)throw new InputMismatchException();
    if(ptrbuf >= lenbuf){
        ptrbuf = 0;
        try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
        if(lenbuf <= 0)return -1;
    }
    return inbuf[ptrbuf++];
}

private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }

private double nd() { return Double.parseDouble(ns()); }
private char nc() { return (char)skip(); }

private String ns()
{
    int b = skip();
    StringBuilder sb = new StringBuilder();
    while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
        sb.appendCodePoint(b);
        b = readByte();
    }
    return sb.toString();
}

private char[] ns(int n)
{
    char[] buf = new char[n];
    int b = skip(), p = 0;
    while(p < n && !(isSpaceChar(b))){
        buf[p++] = (char)b;
        b = readByte();
    }
    return n == p ? buf : Arrays.copyOf(buf, p);
}

private char[][] nm(int n, int m)
{
    char[][] map = new char[n][];
    for(int i = 0;i < n;i++)map[i] = ns(m);
    return map;
}

private int[] na(int n)
{
    int[] a = new int[n];
    for(int i = 0;i < n;i++)a[i] = ni();
    return a;
}

private int ni()
{
    int num = 0, b;
    boolean minus = false;
    while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
    if(b == '-'){
        minus = true;
        b = readByte();
    }

    while(true){
        if(b >= '0' && b <= '9'){
            num = num * 10 + (b - '0');
        }else{
            return minus ? -num : num;
        }
        b = readByte();
    }
}

private long nl()
{
    long num = 0;
    int b;
    boolean minus = false;
    while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
    if(b == '-'){
        minus = true;
        b = readByte();
    }

    while(true){
        if(b >= '0' && b <= '9'){
            num = num * 10 + (b - '0');
        }else{
            return minus ? -num : num;
        }
        b = readByte();
    }
}

private static void tr(Object... o) { System.out.println(Arrays.deepToString(o)); }

}