418_Sentence_Screen_Fitting

Author: partho-maple

README.md

@@ -781,6 +781,7 @@ BFS, DFS, Dijkstra, Floyd–Warshall, Bellman-Ford, Kruskal, Prim's, Minimum Spa
 |57| **[338. Counting Bits](https://tinyurl.com/y5ly38nj)** | [Python](https://tinyurl.com/wu6rdaw/338_Counting_Bits.py), [Swift](https://tinyurl.com/wuja3c4/338_Counting_Bits.swift)|  | Medium | --- |
 |58| **[1269. Number of Ways to Stay in the Same Place After Some Steps](https://tinyurl.com/y43jo8j3)** | [Python](https://tinyurl.com/wu6rdaw/1269_Number_of_Ways_to_Stay_in_the_Same_Place_After_Some_Steps.py), [Swift](https://tinyurl.com/wuja3c4/1269_Number_of_Ways_to_Stay_in_the_Same_Place_After_Some_Steps.swift)| [Art 1](https://tinyurl.com/yynv9xe2) | Hard | Loved the problem. Very versatile |
 |59| **[1277. Count Square Submatrices with All Ones](https://tinyurl.com/y6a82a9r)** | [Python](https://tinyurl.com/wu6rdaw/1277_Count_Square_Submatrices_with_All_Ones.py), [Swift](https://tinyurl.com/wuja3c4/1277_Count_Square_Submatrices_with_All_Ones.swift)| [Must](https://tinyurl.com/y4sa8zgk) | Medium | --- |
+|59| [418. Sentence Screen Fitting](https://tinyurl.com/yhtu7lld) | [Swift](https://tinyurl.com/wuja3c4/418_Sentence_Screen_Fitting.swift)| [Art 1](https://tinyurl.com/yh4xt84c) | Medium | --- |
 
 
 </p>

leetcode.com/swift/DS_ALGO_PRAC.playground/Sources/swift/418_Sentence_Screen_Fitting .swift

@@ -0,0 +1,60 @@
+// Naive solution. O(row*col). TLE
+class Solution {
+    func wordsTyping(_ sentence: [String], _ rows: Int, _ cols: Int) -> Int {
+        var (count, currentWordIndex) = (0, 0)
+        for _ in 0..<rows {
+            var col = -1
+            while col < cols {
+                col += Array(sentence[currentWordIndex]).count
+                if col < cols {
+                    col += 1
+                    currentWordIndex += 1
+                    if currentWordIndex >= sentence.count {
+                        currentWordIndex = 0
+                        count += 1
+                    }
+                }
+            }
+        }
+        return count
+    }
+}
+
+// DP. O(row*sentenceCount)
+class Solution {
+    func wordsTyping(_ sentence: [String], _ rows: Int, _ cols: Int) -> Int {
+        for word in sentence {
+            if word.count > cols {
+                return 0
+            }
+        }
+        
+        var memo = [Int:(Int, Int)]() // CurrentWordIndex: (SentenceCountInCurrentRow, StartingWordIndexOfNextRow)
+        var (totalSentenceCount, currentRowStartWordIndex) = (0, 0)
+        for _ in 0..<rows {
+            if let (currentSentenceCount, nextRowStartWordIndex) = memo[currentRowStartWordIndex] {
+                totalSentenceCount += currentSentenceCount
+                currentRowStartWordIndex = nextRowStartWordIndex
+            } else {
+                var (currentCol, currentRowSentenceCount, currentIndex) = (0, 0, currentRowStartWordIndex)
+                while currentCol < cols {
+                    let wordLen = Array(sentence[currentIndex]).count
+                    if currentCol + wordLen <= cols {
+                        currentCol += (wordLen + 1)
+                        currentIndex = (currentIndex + 1) % sentence.count
+                        if currentIndex == 0 {
+                            currentRowSentenceCount += 1
+                        }
+                    } else {
+                        break
+                    }
+                }
+                totalSentenceCount += currentRowSentenceCount
+                memo[currentRowStartWordIndex] = (currentRowSentenceCount, currentIndex)
+                currentRowStartWordIndex = currentIndex
+            }
+        }
+        
+        return totalSentenceCount
+    }
+}