2022. Convert 1D Array Into 2D Array: AC

Author: tan-wei

src/solution/mod.rs

@@ -1523,3 +1523,4 @@ mod s2016_maximum_difference_between_increasing_elements;
 mod s2017_grid_game;
 mod s2018_check_if_word_can_be_placed_in_crossword;
 mod s2019_the_score_of_students_solving_math_expression;
+mod s2022_convert_1d_array_into_2d_array;

src/solution/s2022_convert_1d_array_into_2d_array.rs

@@ -0,0 +1,101 @@
+/**
+ * [2022] Convert 1D Array Into 2D Array
+ *
+ * You are given a 0-indexed 1-dimensional (1D) integer array original, and two integers, m and n. You are tasked with creating a 2-dimensional (2D) array with  m rows and n columns using all the elements from original.
+ * The elements from indices 0 to n - 1 (inclusive) of original should form the first row of the constructed 2D array, the elements from indices n to 2 * n - 1 (inclusive) should form the second row of the constructed 2D array, and so on.
+ * Return an m x n 2D array constructed according to the above procedure, or an empty 2D array if it is impossible.
+ *  
+ * Example 1:
+ * <img src="https://assets.leetcode.com/uploads/2021/08/26/image-20210826114243-1.png" style="width: 500px; height: 174px;" />
+ * Input: original = [1,2,3,4], m = 2, n = 2
+ * Output: [[1,2],[3,4]]
+ * Explanation: The constructed 2D array should contain 2 rows and 2 columns.
+ * The first group of n=2 elements in original, [1,2], becomes the first row in the constructed 2D array.
+ * The second group of n=2 elements in original, [3,4], becomes the second row in the constructed 2D array.
+ *
+ * Example 2:
+ *
+ * Input: original = [1,2,3], m = 1, n = 3
+ * Output: [[1,2,3]]
+ * Explanation: The constructed 2D array should contain 1 row and 3 columns.
+ * Put all three elements in original into the first row of the constructed 2D array.
+ *
+ * Example 3:
+ *
+ * Input: original = [1,2], m = 1, n = 1
+ * Output: []
+ * Explanation: There are 2 elements in original.
+ * It is impossible to fit 2 elements in a 1x1 2D array, so return an empty 2D array.
+ *
+ *  
+ * Constraints:
+ *
+ * 	1 <= original.length <= 5 * 10^4
+ * 	1 <= original[i] <= 10^5
+ * 	1 <= m, n <= 4 * 10^4
+ *
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.com/problems/convert-1d-array-into-2d-array/
+// discuss: https://leetcode.com/problems/convert-1d-array-into-2d-array/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+impl Solution {
+    pub fn construct2_d_array(original: Vec<i32>, m: i32, n: i32) -> Vec<Vec<i32>> {
+        if (m * n) as usize != original.len() {
+            return Vec::new();
+        }
+
+        let mut result = Vec::with_capacity(m as usize);
+
+        for i in 0..m {
+            let start = (i * n) as usize;
+            let end = start + n as usize;
+            result.push(original[start..end].to_vec());
+        }
+
+        result
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_2022_example_1() {
+        let original = vec![1, 2, 3, 4];
+        let m = 2;
+        let n = 2;
+
+        let result = vec![vec![1, 2], vec![3, 4]];
+
+        assert_eq!(Solution::construct2_d_array(original, m, n), result);
+    }
+
+    #[test]
+    fn test_2022_example_2() {
+        let original = vec![1, 2, 3];
+        let m = 1;
+        let n = 3;
+
+        let result = vec![vec![1, 2, 3]];
+
+        assert_eq!(Solution::construct2_d_array(original, m, n), result);
+    }
+
+    #[test]
+    fn test_2022_example_3() {
+        let original = vec![1, 2];
+        let m = 1;
+        let n = 1;
+
+        let result = vec![];
+
+        assert_eq!(Solution::construct2_d_array(original, m, n), result);
+    }
+}