Create 2075-decode-the-slanted-ciphertext.js

Author: everthis

2075-decode-the-slanted-ciphertext.js

@@ -0,0 +1,29 @@
+/**
+ * @param {string} encodedText
+ * @param {number} rows
+ * @return {string}
+ */
+var decodeCiphertext = function(encodedText, rows) {
+    let n = encodedText.length;
+    let cols = ~~(n / rows);
+    const matrix = Array.from({ length: rows }, () => Array(cols).fill('')) 
+    for (let i = 0; i < rows; i++) {
+        for (let j = 0; j < cols; j++) {
+          matrix[i][j] = encodedText[i * cols + j];
+        }
+    }
+    let ans = "";
+    for (let i = 0; i < cols; i++) {
+        let t = Math.min(rows, cols - i);
+        for (let j = 0; j < t; j++) {
+          ans += matrix[j][i + j];
+        }
+    }
+    let idx = ans.length - 1
+    for(; idx >= 0; idx--) {
+      if(ans[idx] === ' ') continue
+      else break
+    }
+    return ans.slice(0, idx + 1);
+};
+