feat(interview-prep): Transfering Rosetta problems from Curriculum (#34822)

2019-01-30 13:41:15 +05:30
parent 3b5b0e22a7
commit 8584637254
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--- a/curriculum/challenges/english/08-coding-interview-prep/rosetta-code/cut-a-rectangle.md
+++ b/curriculum/challenges/english/08-coding-interview-prep/rosetta-code/cut-a-rectangle.md
@ -0,0 +1,113 @@
+---
+id: 5a23c84252665b21eecc7e06
+title: Cut a rectangle
+challengeType: 5
+---
+
+## Description
+<section id='description'>
+A given rectangle is made from <i>m</i> × <i>n</i> squares. If <i>m</i> and <i>n</i> are not both odd, then it is possible to cut a path through the rectangle along the square edges such that the rectangle splits into two connected pieces with the same shape (after rotating one of the pieces by 180°). All such paths for 2 × 2 and 4 × 3 rectangles are shown below.
+<a href="http://rosettacode.org/wiki/file:rect-cut.svg">file:rect-cut.svg</a>
+Write a function that calculates the number of different ways to cut an <i>m</i> × <i>n</i> rectangle.
+</section>
+
+## Instructions
+<section id='instructions'>
+
+</section>
+
+## Tests
+<section id='tests'>
+
+``` yml
+tests:
+  - text: <code>cutRectangle</code> should be a function.
+    testString: assert(typeof cutRectangle == 'function', '<code>cutRectangle</code> should be a function.');
+  - text: <code>cutRectangle(2, 2)</code> should return a number.
+    testString: assert(typeof cutRectangle(2, 2) == 'number', '<code>cutRectangle(2, 2)</code> should return a number.');
+  - text: <code>cutRectangle(2, 2)</code> should return <code>2</code>.
+    testString: assert.equal(cutRectangle(2, 2), 2, '<code>cutRectangle(2, 2)</code> should return <code>2</code>.');
+  - text: <code>cutRectangle(4, 3)</code> should return <code>9</code>.
+    testString: assert.equal(cutRectangle(4, 3), 9, '<code>cutRectangle(4, 3)</code> should return <code>9</code>.');
+  - text: <code>cutRectangle(4, 4)</code> should return <code>22</code>.
+    testString: assert.equal(cutRectangle(4, 4), 22, '<code>cutRectangle(4, 4)</code> should return <code>22</code>.');
+  - text: <code>cutRectangle(8, 3)</code> should return <code>53</code>.
+    testString: assert.equal(cutRectangle(8, 3), 53, '<code>cutRectangle(8, 3)</code> should return <code>53</code>.');
+  - text: <code>cutRectangle(7, 4)</code> should return <code>151</code>.
+    testString: assert.equal(cutRectangle(7, 4), 151, '<code>cutRectangle(7, 4)</code> should return <code>151</code>.');
+```
+
+</section>
+
+## Challenge Seed
+<section id='challengeSeed'>
+<div id='js-seed'>
+
+```js
+function cutRectangle (w, h) {
+  // Good luck!
+}
+```
+
+</div>
+</section>
+
+## Solution
+<section id='solution'>
+
+```js
+function cutRectangle (w, h) {
+  if (w % 2 == 1 && h % 2 == 1)
+    return;
+
+  var dirs = [[0, -1], [-1, 0], [0, 1], [1, 0]];
+
+  var grid = new Array(h); for (var i = 0; i < grid.length; i++) grid[i]=new Array(w);
+  var stack = [];
+
+  var half = Math.floor((w * h) / 2);
+  var bits = Math.pow(2, half) - 1;
+  var result=0;
+  for (; bits > 0; bits -= 2) {
+
+    for (var i = 0; i < half; i++) {
+      var r = Math.floor(i / w);
+      var c = i % w;
+      grid[r][c] = (bits & (1 << i)) != 0 ? 1 : 0;
+      grid[h - r - 1][w - c - 1] = 1 - grid[r][c];
+    }
+
+    stack.push(0);
+    grid[0][0] = 2;
+    var count = 1;
+    while (stack.length!=0) {
+
+      var pos = stack.pop();
+      var r = Math.floor(pos / w);
+      var c = pos % w;
+
+      for (var dir of dirs) {
+        var nextR = r + dir[0];
+        var nextC = c + dir[1];
+
+        if (nextR >= 0 && nextR < h && nextC >= 0 && nextC < w) {
+
+          if (grid[nextR][nextC] == 1) {
+            stack.push(nextR * w + nextC);
+            grid[nextR][nextC] = 2;
+            count++;
+          }
+        }
+      }
+    }
+
+    if (count == half) {
+      result++;
+    }
+  }
+
+  return result;
+}
+```
+
+</section>