[Leetcode#6] Zigzag conversion

letscode.io · letscode.io · commit 6695b8b074eb · 2020-03-22T20:42:40.000+01:00
diff --git a/leetcode/6_zigzag_conversion.js b/leetcode/6_zigzag_conversion.js
@@ -0,0 +1,39 @@
+/**
+ * @param {string} s
+ * @param {number} numRows
+ * @return {string}
+ */
+var convert = function(s, numRows) {
+  const chars = s.split("")
+  const zigzag = [];
+
+  let currentColumn = 0
+
+  while (chars.length > 0) {
+    let column
+
+    if (numRows == 1 || currentColumn === 0 || currentColumn % (numRows - 1) === 0) {
+      column = chars.splice(0, numRows)
+    } else {
+      column = new Array(numRows).fill(null);
+      const elementIndex = numRows - 1 - (currentColumn % (numRows - 1));
+      column[elementIndex] = chars.shift()
+    }
+
+    zigzag.push(column)
+
+    currentColumn += 1
+  }
+
+  let result = '';
+  for (let rowIndex = 0; rowIndex < numRows; rowIndex++) {
+    for (let columnIndex = 0; columnIndex < zigzag.length; columnIndex++) {
+      const char = zigzag[columnIndex][rowIndex]
+
+      if (char) {
+        result += char
+      }
+    }
+  }
+  return result;
+};
