Algorithm 2 Three-category-based Scheme $(N,K,M)$

procedure  PLACEMENT($W_1,\dots ,W_N$)   1:Apply Algorithm 1 MAN Uncoded Symmetric Placement Scheme ($N,K,M,W_{\left[N\right]}$) end procedure    procedure  DELIVERY($\mathcal{R},D_{\mathcal{R}}$)   2: $r\leftarrow |D_{\mathcal{R}}|$   3: $t\leftarrow KM/N$   4:$N_e\left(D_{\mathcal{R}}\right)\leftarrow$ the number of distinct elements in $D_{\mathcal{R}}$   5:for  $k\in \left[K\right]\setminus \mathcal{R}$  do   6:  ${\mathcal{U}}^{\prime k}\leftarrow \{u_1^{\prime k},\dots ,u_{N_e\left(D_{\mathcal{R}}\right)}^{\prime k}\}$   7: end for   8:(i) For sub-files in the first category:   9: $\mathcal{T}\leftarrow \{𝒯\subseteq [K]\setminus \mathcal{R}:|𝒯|=t\}$ 10:for  $𝒯\in \mathcal{T}$ do 11: for  $n\in \left[N\right]$  do 12:  Divide sub-file $W_{n,𝒯}$ into t disjoint sub-pieces ($W_{n,𝒯,a}:a\in 𝒯$) with equal size 13: end for 14: for  $a\in 𝒯$  do 15:  for  $s\in {\mathcal{U}}^{\prime a}$  do 16:   User a transmit $X_a^{1\mathrm{st},d_s,𝒯}=W_{d_s,𝒯,a}$ 17:  end for 18: end for 19: end for 20:(ii) For sub-files in the second category: 21:for  $\in [max\{1,t+r-K\},min\{t-1,r-1\left\}\right]$  do 22: Ɓ  $\leftarrow \{\widehat{\mathcal{B}}\subseteq \left[K\right]\setminus \mathcal{R}:|\widehat{\mathcal{B}}|=t-i\}$ 23: for  $\widehat{\mathcal{B}}\in$ Ɓ  do 24:  for  $\mathcal{B}\subset \mathcal{R}:\left|\mathcal{B}\right|=i$  do 25:   for  $n\in \left[N\right]$  do 26:    Divide sub-file $W_{n,\mathcal{B}\cup \widehat{\mathcal{B}}}$ into $t-i$ disjoint sub-pieces ($W_{n,\mathcal{B}\cup \widehat{\mathcal{B}},b}:b\in \widehat{\mathcal{B}}$) with equal size 27:   end for 28:  end for 29:  for  $b\in \widehat{\mathcal{B}}$  do 30:   for  $\overline{\mathcal{B}}\subseteq \mathcal{R}:\left|\overline{\mathcal{B}}\right|=i+1$  do 31:    if  $\overline{\mathcal{B}}\cap {\mathcal{U}}^{\prime b}==\varnothing$  then 32:     continue 33:    else 34:     User b transmits $X_b^{2\mathrm{nd},d_x,\widehat{\mathcal{B}}\bigcup \overline{\mathcal{B}}\setminus \left\{x\right\}}=\underset{x\in \overline{\mathcal{B}}}{⨁}{W}_{d_x,\widehat{\mathcal{B}}\cup \overline{\mathcal{B}}\setminus \left\{x\right\},b}$ 35:    end if 36:   end for 37:  end for 38: end for 39: end for 40:(iii) For sub-files in the third category: 41:𝒢  $\leftarrow \{\mathcal{G}\subseteq [K]:|\mathcal{G}|=t\}$ 42:for  $n\in \left[N\right]$  do 43: for  $\mathcal{G}\in$ 𝒢  do 44:  Divide sub-file $W_{n,\mathcal{G}}$ into t disjoint sub-pieces $(W_{n,\mathcal{G},i}:i\in \mathcal{G})$ with equal size 45: end for 46: end for 47:for  $i\in \mathcal{R}$  do 48: $N_e\left(D_{\mathcal{R}\setminus \left\{i\right\}}\right)\leftarrow$ the number of distinct elements in $D_{\mathcal{R}\setminus \left\{i\right\}}$ 49:  ${\mathcal{U}}^i\leftarrow \{u_1^i,...,u_{N_e\left(D_{\mathcal{R}\setminus \left\{i\right\}}\right)}^i\}$ 50: for ${\mathcal{E}}^i\subseteq \mathcal{R}\setminus \left\{i\right\}:\left|{\mathcal{E}}^i\right|=t$ users do 51:  if  ${\mathcal{E}}^i\cap {\mathcal{U}}^i==\varnothing$  then 52:   continue 53:  else 54:   User i transmits $Y_{{\mathcal{E}}^i}^i=\underset{k\in {\mathcal{E}}^i}{⨁}{W}_{d_k,\{{\mathcal{E}}^i\cup \left\{i\right\}\}\setminus \left\{k\right\},i}$ 55:  end if 56: end for 57: end for end procedure