solve 6

Author: shandowc

src/solution/mod.rs

@@ -2,3 +2,4 @@ mod s0001_two_sum;
 mod s0002_add_two_numbers;
 mod s0003_longest_substring_without_repeating_characters;
 mod s0005_longest_palindromic_substring;
+mod s0006_zigzag_conversion;

src/solution/s0006_zigzag_conversion.rs

@@ -0,0 +1,103 @@
+use std::rc::Rc;
+
+/**
+ * [6] N 字形变换
+ *
+ * 将一个给定字符串 s 根据给定的行数 numRows ，以从上往下、从左到右进行 Z 字形排列。
+ * 比如输入字符串为 "PAYPALISHIRING" 行数为 3 时，排列如下：
+ *
+ * P   A   H   N
+ * A P L S I I G
+ * Y   I   R
+ * 之后，你的输出需要从左往右逐行读取，产生出一个新的字符串，比如："PAHNAPLSIIGYIR"。
+ * 请你实现这个将字符串进行指定行数变换的函数：
+ *
+ * string convert(string s, int numRows);
+ *
+ * 示例 1：
+ *
+ * 输入：s = "PAYPALISHIRING", numRows = 3
+ * 输出："PAHNAPLSIIGYIR"
+ * 示例 2：
+ *
+ * 输入：s = "PAYPALISHIRING", numRows = 4
+ * 输出："PINALSIGYAHRPI"
+ * 解释：
+ * P     I    N
+ * A   L S  I G
+ * Y A   H R
+ * P     I
+ *
+ * 示例 3：
+ *
+ * 输入：s = "A", numRows = 1
+ * 输出："A"
+ *
+ *
+ * 提示：
+ *
+ * 	1 <= s.length <= 1000
+ * 	s 由英文字母（小写和大写）、',' 和 '.' 组成
+ * 	1 <= numRows <= 1000
+ *
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.cn/problems/zigzag-conversion/
+// discuss: https://leetcode.cn/problems/zigzag-conversion/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+
+impl Solution {
+    pub fn convert(s: String, num_rows: i32) -> String {
+        if num_rows < 2 {
+            return s.into();
+        }
+        let bytes = s.as_bytes();
+        let mut row: Vec<Vec<u8>> = vec![Vec::with_capacity(s.len()/(num_rows as usize - 1)); num_rows as usize];
+
+        let nums_grp = (num_rows - 1) * 2;
+        for i in (0..s.len()) {
+            let rem = (i as i32) % nums_grp;
+            let row_no = if rem > num_rows - 1 {
+                (num_rows - 1) * 2 - rem
+            } else {
+                rem
+            };
+            row[row_no as usize].push(bytes[i]);
+        }
+        let mut res = Vec::new();
+        for i in (0..num_rows as usize) {
+            res.extend(row[i].iter());
+        }
+        std::str::from_utf8(&res).unwrap().to_owned()
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_6() {
+        assert_eq!(
+            Solution::convert("PAYPALISHIRING".to_string(), 3),
+            "PAHNAPLSIIGYIR"
+        );
+        assert_eq!(
+            Solution::convert("PAYPALISHIRING".to_string(), 4),
+            "PINALSIGYAHRPI"
+        );
+        assert_eq!(
+            Solution::convert("ABC".to_string(), 1),
+            "ABC"
+        );
+        assert_eq!(
+            Solution::convert("ACB".to_string(), 1),
+            "ACB"
+        );
+    }
+}