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The transportation algorithm follows the **same logic as the Simplex method**, but with **simplifications** tailored to the structure of transportation problems:
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### 🔹 1st Phase: Initial Basic Feasible Solution
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We will use two methods to find a basic solution:
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-**Northwest Corner Method**
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-**Least Cost Method**
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These provide starting points for optimization.
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<br>
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### 🔹 2nd Phase: Optimality Check:
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After obtaining a feasible solution, we check for optimality using methods like:
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-**MODI Method** (Modified Distribution)
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-**Stepping Stone Method**
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These determine whether cost can be further reduced by adjusting flows along loops in the matrix.
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<br>
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#
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## 🧭 Northwest Corner Method (Método do Canto Noroeste)
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This is a method to generate an initial feasible solution without considering transportation costs.
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<br>
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### 🔹 Steps:
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1.**Start in the top-left (northwest) corner** of the transportation table.
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- This is always cell $begin:math:text$ x_{11} $end:math:text$.
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2.**Allocate as much as possible** to the selected cell, respecting the available supply and demand.
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3.**Block the row or column** where the supply or demand has been fully used (but only one if both are zero simultaneously).
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- Mark the blocked row/column with an 'x'.
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- This ensures that some basic variables have zero values (necessary for basic feasible solution).
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4.**Repeat** the steps with the next unblocked cell in the top-left of the remaining matrix.
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🔁 Continue until all cells are either allocated or blocked.
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🟢 This method is **simple and quick**, but not necessarily optimal — further optimization is done in the next phase.
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<br>
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#
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## 💸 Least Cost Method (Método do Custo Mínimo)
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This method takes into account the transportation costs to guide the initial allocation.
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<br>
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### 🔹 Steps:
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1.**Identify the cell with the lowest unit cost** in the cost matrix among the remaining unallocated cells.
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2.**Allocate as much as possible** to this cell, without exceeding supply or demand constraints.
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3.**Adjust the supply and demand** for the row and column of the allocated cell.
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4.**Remove** (cross out) the row or column where supply or demand becomes zero. If both are zero simultaneously, cross out only one to maintain feasibility.
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5.**Repeat** the steps until all supplies and demands are met.
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⚠️ Unlike the Northwest Corner, this method **considers the costs** and usually leads to a **better initial solution**, closer to the optimal.
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