✨ zigzag conversion

Author: tangweikun

src/6-zigzag-conversion/index.js

@@ -0,0 +1,46 @@
+/**
+ * @param {string} s
+ * @param {number} numRows
+ * @return {string}
+ */
+var convert = function (s, numRows) {
+  if (numRows === 1) return s;
+  const res = [];
+  let x = 0;
+  let y = 0;
+  let direction = 'DOWN';
+
+  for (let i = 0; i < s.length; i++) {
+    if (!res[y]) {
+      res[y] = '';
+    }
+    res[y] += s[i];
+
+    if (direction === 'DOWN') {
+      if (y + 1 === numRows) {
+        x++;
+        y--;
+        direction = 'RIGHT_UP';
+      } else {
+        y++;
+      }
+
+      continue;
+    }
+
+    if (direction === 'RIGHT_UP') {
+      if (y === 0) {
+        direction = 'DOWN';
+        y++;
+      } else {
+        x++;
+        y--;
+      }
+
+      continue;
+    }
+  }
+
+  return res.reduce((acc, x) => acc + x, '');
+};
+convert('AB', 1);