From 2c193f140d939b6c3dd7fb058d6cd130f3728dd4 Mon Sep 17 00:00:00 2001
From: Bauke <me@bauke.xyz>
Date: Sat, 9 Apr 2022 13:04:21 +0200
Subject: [PATCH] Solve excel-sheet-column-title.

---
 source/excel_sheet_column_title/mod.rs | 18 ++++++++++++++++++
 source/lib.rs                          |  1 +
 tests/excel_sheet_column_title.rs      | 11 +++++++++++
 3 files changed, 30 insertions(+)
 create mode 100644 source/excel_sheet_column_title/mod.rs
 create mode 100644 tests/excel_sheet_column_title.rs

diff --git a/source/excel_sheet_column_title/mod.rs b/source/excel_sheet_column_title/mod.rs
new file mode 100644
index 0000000..8de1795
--- /dev/null
+++ b/source/excel_sheet_column_title/mod.rs
@@ -0,0 +1,18 @@
+pub fn convert_to_title(column: i32) -> String {
+  let radix = 26;
+
+  let mut column = column as u32;
+  let mut result = vec![];
+
+  while column != 0 {
+    // Subtract 1 so the number 0 would equal the value 1.
+    let value = (column - 1) % radix;
+    column = (column - 1) / radix;
+
+    // Add 65 so the modulo'd value will be in the 65 through 90 character range
+    // (upppercase letters).
+    result.push(char::from_u32(value + 65).unwrap());
+  }
+
+  result.into_iter().rev().collect::<String>()
+}
diff --git a/source/lib.rs b/source/lib.rs
index a3d547a..1814c68 100644
--- a/source/lib.rs
+++ b/source/lib.rs
@@ -1,5 +1,6 @@
 pub mod add_binary;
 pub mod excel_sheet_column_number;
+pub mod excel_sheet_column_title;
 pub mod implement_strstr;
 pub mod length_of_last_word;
 pub mod longest_common_prefix;
diff --git a/tests/excel_sheet_column_title.rs b/tests/excel_sheet_column_title.rs
new file mode 100644
index 0000000..1b9d734
--- /dev/null
+++ b/tests/excel_sheet_column_title.rs
@@ -0,0 +1,11 @@
+use leetcode::excel_sheet_column_title::convert_to_title;
+
+use test_case::test_case;
+
+#[test_case(1, "A"; "minimum")]
+#[test_case(i32::MAX, "FXSHRXW"; "maximum")]
+#[test_case(28, "AB"; "double")]
+#[test_case(1377, "AZY"; "triple")]
+fn test_excel_sheet_column_title(input: i32, expected: &str) {
+  assert_eq!(convert_to_title(input), expected);
+}