Add solution

Author: Annahcj

Counting/3330.find-the-original-typed-string-I.js

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+// 3330. Find the Original Typed String I
+// Alice is attempting to type a specific string on her computer. However, she tends to be clumsy and may press a key for too long, resulting in a character being typed multiple times.
+// Although Alice tried to focus on her typing, she is aware that she may still have done this at most once.
+// You are given a string word, which represents the final output displayed on Alice's screen.
+// Return the total number of possible original strings that Alice might have intended to type.
+
+
+// Solution: Counting
+
+// Find the groups of consecutively equal characters with more than one occurrance.
+// For each group, the possible strings is equal to the occurrances in the group - 1.
+// Get the sum of occurrances-1.
+
+// Time Complexity: O(n) 45ms
+// Space Complexity: O(1) 54MB
+function possibleStringCount(word) {
+  let consec = 1, count = 0;
+  const n = word.length;  
+  for (let i = 1; i < n; i++) {
+    if (word[i] === word[i - 1]) {
+      consec++;
+    } else {
+      count += consec > 1 ? consec - 1 : 0;
+      consec = 1;
+    }
+  }
+  if (consec > 1) {
+    count += consec - 1;
+  }
+  return count + 1; // the original string itself
+};
+
+// Three test cases
+console.log(possibleStringCount("abbcccc")) // 5
+console.log(possibleStringCount("abcd")) // 1
+console.log(possibleStringCount("aaaa")) // 4