leetcode

commit e16405943e9eda2fc55689093c666c056249b664
parent 6d780927f23d34e5bfddcde9392c5786d5861461
Author: AndrewLockVI <andrewlaack1@gmail.com>
Date:   Tue,  9 May 2023 17:48:10 -0500

Completed zigzag conversion using dart

Diffstat:
A
zig-zag-conversion/zig-zag-conversion.dart
 | 
56
++++++++++++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 56 insertions(+), 0 deletions(-)
diff --git a/zig-zag-conversion/zig-zag-conversion.dart b/zig-zag-conversion/zig-zag-conversion.dart
@@ -0,0 +1,56 @@
+//Return a string if it were to be placed in a matrix with a  zig zag pattern
+//and then returned read from left to right top to bottom.
+//Ex.
+//Input:
+//ThisQuestionSucks | numRows = 3
+//T q t s c
+//hsusinuk
+//i e o c
+//Output:
+//TQtSshsusinukieoc
+//My solution simulates creating a zigzagged 2d array by 
+//creating the first array and filling it to the height. Then
+//height -2 times moving to the side placing the character one
+//higher each time. At the end the matrix is read and returned.
+//The time complexity of this code is O(n) where n is the length of the
+//string.
+//Time:  860ms Beats: 6.17%
+//Memory: 187.8MB Beats: 6.17%
+
+class Solution {
+  String convert(String s, int numRows) {
+      List<List<String>> zigzag = [];
+      int placed = 0;
+      while(placed < s.length){
+          zigzag.add([]);
+          for(int i = 0 ; i < numRows && placed < s.length; ++i){
+              zigzag[zigzag.length - 1].add(s[placed]);
+              placed += 1;
+          }
+          for(int i = 0 ; i < numRows - 2 ; ++i){
+              zigzag.add([]);
+              for(int x = 0 ; x < numRows - i - 2; ++x){
+                  zigzag[zigzag.length - 1].add("");
+              }
+              if(placed < s.length){
+                zigzag[zigzag.length - 1].add(s[placed]);
+                placed += 1;
+              }
+              else{
+                  break;
+              }
+
+          }
+      }
+      String ret_val = "";
+      for(int x = 0 ; x < zigzag[0].length; ++x){
+        for(int i = 0 ; i < zigzag.length ; ++i){
+            if(zigzag[i].length - 1 >= x){
+                ret_val += zigzag[i][x];
+            }
+          }
+      }
+
+      return ret_val;
+  }
+}