update 72

Author: geemaple

README.md

@@ -16,7 +16,7 @@ This is an open-source project that is continually updated
 
 **Total:** 433 problems
 
-**Updated:** 2024-09-10 15:17:59
+**Updated:** 2024-09-10 18:44:26
 
 ## 链接/Links
 
@@ -214,7 +214,6 @@ python problem.py https://www.lintcode.com/problem/92 -l cpp
 | 2024-07 | [Leetcode-416. Partition Equal Subset Sum](https://leetcode.com/problems/partition-equal-subset-sum/description/) | [c++](./leetcode/416.partition-equal-subset-sum.cpp), [python3](./leetcode/416.partition-equal-subset-sum.py) | Dynamic Programming | O\(N^2\) | O\(N\) | - |
 | 2024-07 | [Leetcode-474. Ones And Zeroes](https://leetcode.com/problems/ones-and-zeroes/description/) | [c++](./leetcode/474.ones-and-zeroes.cpp), [python3](./leetcode/474.ones-and-zeroes.py) | Dynamic Programming | O\(KMN\) | O\(MN\) | - |
 | 2024-07 | [Leetcode-322. Coin Change](https://leetcode.com/problems/coin-change/description/) | [c++](./leetcode/322.coin-change.cpp), [python3](./leetcode/322.coin-change.py) | Dynamic Programming | O\(K \* N\) | O\(N\) | [Video](https://youtu.be/EjMjlFjLRiM) |
-| 2024-07 | [Leetcode-72. Edit Distance](https://leetcode.com/problems/edit-distance/description/) | [c++](./leetcode/72.edit-distance.cpp), [python3](./leetcode/72.edit-distance.py) | Dynamic Programming | O\(MN\) | O\(MN\) | - |
 | 2024-07 | [Leetcode-650. 2 Keys Keyboard](https://leetcode.com/problems/2-keys-keyboard/description/) | [c++](./leetcode/650.2-keys-keyboard.cpp), [python3](./leetcode/650.2-keys-keyboard.py) | Dynamic Programming | \- | \- | - |
 | 2024-07 | [Leetcode-10. Regular Expression Matching](https://leetcode.com/problems/regular-expression-matching/description/) | [c++](./leetcode/10.regular-expression-matching.cpp), [python3](./leetcode/10.regular-expression-matching.py) | Dynamic Programming | O\(MN\) | O\(MN\) | - |
 | 2024-07 | [Leetcode-213. House Robber II](https://leetcode.com/problems/house-robber-ii/description/) | [c++](./leetcode/213.house-robber-ii.cpp), [python3](./leetcode/213.house-robber-ii.py) | Dynamic Programming | O\(N\) | O\(N\) | - |
@@ -243,6 +242,7 @@ python problem.py https://www.lintcode.com/problem/92 -l cpp
 | 2024-09 | [Leetcode-188. Best Time To Buy And Sell Stock IV](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-iv/description/) | [c++](./leetcode/188.best-time-to-buy-and-sell-stock-iv.cpp), [python3](./leetcode/188.best-time-to-buy-and-sell-stock-iv.py) | Dynamic Programming | O\(NK\) | O\(NK\) | - |
 | 2024-09 | [Leetcode-714. Best Time To Buy And Sell Stock With Transaction Fee](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-with-transaction-fee/description/) | [c++](./leetcode/714.best-time-to-buy-and-sell-stock-with-transaction-fee.cpp), [python3](./leetcode/714.best-time-to-buy-and-sell-stock-with-transaction-fee.py) | Dynamic Programming | O\(N\) | O\(N\) | - |
 | 2024-09 | [Leetcode-309. Best Time To Buy And Sell Stock With Cooldown](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-with-cooldown/description/) | [c++](./leetcode/309.best-time-to-buy-and-sell-stock-with-cooldown.cpp), [python3](./leetcode/309.best-time-to-buy-and-sell-stock-with-cooldown.py) | Dynamic Programming | O\(N\) | O\(N\) | - |
+| 2024-09 | [Leetcode-72. Edit Distance](https://leetcode.com/problems/edit-distance/description/) | [c++](./leetcode/72.edit-distance.cpp), [python3](./leetcode/72.edit-distance.py) | Dynamic Programming | O\(MN\) | O\(MN\) | - |
 
 ## Binary Search
 

leetcode/72.edit-distance.cpp

@@ -65,4 +65,40 @@ class Solution {
         return dp[m][n];
 
     }
+};
+
+class Solution {
+public:
+    int minDistance(string word1, string word2) {
+        int n = word1.size();
+        int m = word2.size();
+        vector<vector<int>> cache(n, vector<int>(m, INT_MAX));
+        return helper(word1, word2, 0, 0, cache);
+    }
+
+    int helper(string &word1, string &word2, int i, int j, vector<vector<int>> &cache) {
+        if (i == word1.size()) {
+            return word2.size() - j;
+        }
+
+        if (j == word2.size()) {
+            return word1.size() - i;
+        }
+
+        if (cache[i][j] != INT_MAX) {
+            return cache[i][j];
+        }
+
+        if (word1[i] == word2[j]) {
+            cache[i][j] = helper(word1, word2, i + 1, j + 1, cache);
+        } else {
+            int insert = helper(word1, word2, i, j + 1, cache) + 1;
+            int remove = helper(word1, word2, i + 1, j, cache) + 1;
+            int replace = helper(word1, word2, i + 1, j + 1, cache) + 1;
+
+            cache[i][j] = min(min(insert, remove), replace);
+        }
+
+        return cache[i][j];
+    }
 };

leetcode/72.edit-distance.py

@@ -57,4 +57,32 @@ def minDistance(self, word1: str, word2: str) -> int:
                 else:
                     dp[i][j] = min(dp[i - 1][j - 1], dp[i - 1][j], dp[i][j - 1]) + 1
 
-        return dp[m][n]
+        return dp[m][n]
+
+
+class Solution:
+    def minDistance(self, word1: str, word2: str) -> int:
+        n = len(word1)
+        m = len(word2)
+        cache = [[None] * m for i in range(n)]
+        return self.helper(word1, word2, 0, 0, cache) # dict cache is too slow
+
+    def helper(self, word1: str, word2: str, i :int, j: int, cache: dict) -> int:
+        if i == len(word1):
+            return len(word2) - j
+
+        if j == len(word2):
+            return len(word1) - i
+
+        if cache[i][j] is not None:
+            return cache[i][j]
+
+        if word1[i] == word2[j]:
+            cache[i][j] = self.helper(word1, word2, i + 1, j + 1, cache)
+        else:
+            insert = self.helper(word1, word2, i, j + 1, cache) + 1
+            delete = self.helper(word1, word2, i + 1, j, cache) + 1
+            replace = self.helper(word1, word2, i + 1, j + 1, cache) + 1
+            cache[i][j] = min(insert, delete, replace)
+
+        return cache[i][j]