diff --git a/Array/LeftmostColumnLeastOne.swift b/Array/LeftmostColumnLeastOne.swift
new file mode 100644
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--- /dev/null
+++ b/Array/LeftmostColumnLeastOne.swift
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+/**
+ * Question Link: https://leetcode.com/problems/leftmost-column-with-at-least-a-one/
+ * Primary idea: Iterate through top right and then move left down 
+ *
+ * Time Complexity: O(m + n), Space Complexity: O(1)
+ *
+ */
+
+/**
+ * // This is the BinaryMatrix's API interface.
+ * // You should not implement it, or speculate about its implementation
+ * public class BinaryMatrix {
+ *     public func get(_ row: Int, _ col: Int) -> Int {}
+ *     public func dimensions() -> [Int] {}
+ * };
+ */
+
+class LeftmostColumnLeastOne {
+    func leftMostColumnWithOne(_ binaryMatrix: BinaryMatrix) -> Int {
+        let dimensions = binaryMatrix.dimensions()
+        let m = dimensions[0], n = dimensions[1]
+        var row = 0, col = n - 1, res = -1
+
+        while row < m && col >= 0 {
+            if binaryMatrix.get(row, col) == 0 {
+                row += 1
+            } else {
+                res = col
+                col -= 1
+            }
+        }
+
+        return res
+    }
+}