From 91edf9d592e4c5c3636fa7e14e35dc8e50e90904 Mon Sep 17 00:00:00 2001
From: yi-ge <a@wyr.me>
Date: Sun, 26 Jun 2022 21:19:02 +0800
Subject: [PATCH] =?UTF-8?q?add:=20Z=20=E5=AD=97=E5=BD=A2=E5=8F=98=E6=8D=A2?=
MIME-Version: 1.0
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---
 .vscode/settings.json                |  3 +++
 README.md                            |  4 ++++
 src/array/zigzag-conversion.ts       | 16 ++++++++++++++++
 test/array/zigzag-conversion.test.ts |  8 ++++++++
 4 files changed, 31 insertions(+)
 create mode 100644 src/array/zigzag-conversion.ts
 create mode 100644 test/array/zigzag-conversion.test.ts

diff --git a/.vscode/settings.json b/.vscode/settings.json
index 1f9c99f..9a0129a 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -23,6 +23,9 @@
     "mincost",
     "nums",
     "Paddr",
+    "PAHNAPLSIIGYIR",
+    "PAYPALISHIRING",
+    "PINALSIGYAHRPI",
     "powx",
     "preorder",
     "Prinme",
diff --git a/README.md b/README.md
index a17371a..23c1c7a 100644
--- a/README.md
+++ b/README.md
@@ -391,6 +391,10 @@ TypeScript / JavaScript 基础算法、数据结构练习，包含 LeetCode 或
 
   - LeetCode 710. 黑名单中的随机数 <https://leetcode.cn/problems/random-pick-with-blacklist/>
 
+- [Z 字形变换](src/array/zigzag-conversion.ts)
+
+  - LeetCode 6. Z 字形变换 <https://leetcode.cn/problems/zigzag-conversion/>
+
 ## 栈
 
 - [最大矩阵](src/stack/maximal-rectangle.js)
diff --git a/src/array/zigzag-conversion.ts b/src/array/zigzag-conversion.ts
new file mode 100644
index 0000000..4dbd705
--- /dev/null
+++ b/src/array/zigzag-conversion.ts
@@ -0,0 +1,16 @@
+export function convert (s: string, numRows: number): string {
+  if (numRows === 1) return s
+  const res = new Array(numRows).fill('')
+
+  for (let i = 0, len = s.length, isDown = true, row = 0; i < len; i++) {
+    res[isDown ? row++ : row--] += s[i]
+
+    if (row === numRows - 1) {
+      isDown = false
+    } else if (row === 0) {
+      isDown = true
+    }
+  }
+
+  return res.join('')
+}
\ No newline at end of file
diff --git a/test/array/zigzag-conversion.test.ts b/test/array/zigzag-conversion.test.ts
new file mode 100644
index 0000000..856dda9
--- /dev/null
+++ b/test/array/zigzag-conversion.test.ts
@@ -0,0 +1,8 @@
+import { convert } from '../../src/array/zigzag-conversion'
+
+test('Z 字形变换', () => {
+  expect(convert('PAYPALISHIRING', 3)).toBe('PAHNAPLSIIGYIR')
+  expect(convert('PAYPALISHIRING', 4)).toBe('PINALSIGYAHRPI')
+  expect(convert('A', 1)).toBe('A')
+  expect(convert('AB', 1)).toBe('AB')
+})
\ No newline at end of file