Merge pull request #61 from purnasth/backspace/solution

Chayandas07 · web-flow · commit 901f0d8671f7 · 2023-10-27T00:04:35.000+05:30
feat: Backspace String Compare Problem JavaScript
diff --git a/Backspace_string_compare/index.html b/Backspace_string_compare/index.html
@@ -0,0 +1,35 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Backspace String Compare</title>
+  </head>
+  <body>
+    <button onclick="showCustomDialog()">Compare Strings</button>
+
+    <div id="custom-dialog" style="display: none">
+      <p id="result-text">Result will be displayed here</p>
+    </div>
+
+    <script>
+      function showCustomDialog() {
+        const customDialog = document.getElementById("custom-dialog");
+        const resultText = document.getElementById("result-text");
+
+        const s = prompt("Enter the first string:");
+        const t = prompt("Enter the second string:");
+        const result = backspaceCompare(s, t);
+
+        customDialog.style.display = "block";
+
+        if (result) {
+          resultText.innerHTML = `Are the first input "${s}" and the second input "${t}" equal after considering backspaces?<br><span style="color: green;">True</span>`;
+        } else {
+          resultText.innerHTML = `Are the first input "${s}" and the second input "${t}" equal after considering backspaces?<br><span style="color: red;">False</span>`;
+        }
+      }
+    </script>
+    <script src="./solution.js"></script>
+  </body>
+</html>
diff --git a/Backspace_string_compare/solution.js b/Backspace_string_compare/solution.js
@@ -0,0 +1,39 @@
+// Backspace String Compare Logic Starts Here
+const backspaceCompare = (s, t) => {
+  const getNextValidCharIndex = (str, index) => {
+    let backspaceCount = 0;
+    while (index >= 0) {
+      if (str[index] === "#") {
+        backspaceCount++;
+        index--;
+      } else if (backspaceCount > 0) {
+        backspaceCount--;
+        index--;
+      } else {
+        break;
+      }
+    }
+    return index;
+  };
+
+  let sPointer = s.length - 1;
+  let tPointer = t.length - 1;
+
+  while (sPointer >= 0 || tPointer >= 0) {
+    sPointer = getNextValidCharIndex(s, sPointer);
+    tPointer = getNextValidCharIndex(t, tPointer);
+
+    if (sPointer < 0 && tPointer < 0) {
+      return true;
+    }
+
+    if (sPointer < 0 || tPointer < 0 || s[sPointer] !== t[tPointer]) {
+      return false;
+    }
+
+    sPointer--;
+    tPointer--;
+  }
+
+  return true;
+};
