Day1269 done

Author: WorkWithAfridi

Dart/RotateNxNMatrix90DegreeClockwise.dart

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+// This problem was asked by Facebook.
+
+// Given an N by N matrix, rotate it by 90 degrees clockwise.
+
+// For example, given the following matrix:
+
+// [[1, 2, 3],
+//  [4, 5, 6],
+//  [7, 8, 9]]
+// you should return:
+
+// [[7, 4, 1],
+//  [8, 5, 2],
+//  [9, 6, 3]]
+// Follow-up: What if you couldn't use any extra space?
+
+main() {
+  List<List<int>> givenMatrix = [
+    [1, 2, 3],
+    [4, 5, 6],
+    [7, 8, 9]
+  ];
+
+  int N = givenMatrix.first.length;
+  print("N: $N");
+  print("Initial matrix: ${givenMatrix}");
+
+  for (int i = 0; i < givenMatrix.length; i++) {
+    for (int j = 0; j < givenMatrix.length; j++) {
+      givenMatrix[j].add(givenMatrix[i][j]);
+    }
+  }
+
+  for (int i = 0; i < givenMatrix.length; i++) {
+    givenMatrix[i].removeRange(0, N);
+    givenMatrix[i] = givenMatrix[i].reversed.toList();
+  }
+  print("rotated matrix: ${givenMatrix}");
+}