Add the initial EN translation for C++ code (#1346)

2026-02-10 14:15:37 +08:00 · 2024-05-06 13:31:46 +08:00
parent 9e4017b3fb
commit 8e60d12151
111 changed files with 6993 additions and 9 deletions
--- a/en/codes/cpp/chapter_dynamic_programming/edit_distance.cpp
+++ b/en/codes/cpp/chapter_dynamic_programming/edit_distance.cpp
@@ -0,0 +1,136 @@
+/**
+ * File: edit_distance.cpp
+ * Created Time: 2023-07-13
+ * Author: krahets (krahets@163.com)
+ */
+
+#include "../utils/common.hpp"
+
+/* Edit distance: Brute force search */
+int editDistanceDFS(string s, string t, int i, int j) {
+    // If both s and t are empty, return 0
+    if (i == 0 && j == 0)
+        return 0;
+    // If s is empty, return the length of t
+    if (i == 0)
+        return j;
+    // If t is empty, return the length of s
+    if (j == 0)
+        return i;
+    // If the two characters are equal, skip these two characters
+    if (s[i - 1] == t[j - 1])
+        return editDistanceDFS(s, t, i - 1, j - 1);
+    // The minimum number of edits = the minimum number of edits from three operations (insert, remove, replace) + 1
+    int insert = editDistanceDFS(s, t, i, j - 1);
+    int del = editDistanceDFS(s, t, i - 1, j);
+    int replace = editDistanceDFS(s, t, i - 1, j - 1);
+    // Return the minimum number of edits
+    return min(min(insert, del), replace) + 1;
+}
+
+/* Edit distance: Memoized search */
+int editDistanceDFSMem(string s, string t, vector<vector<int>> &mem, int i, int j) {
+    // If both s and t are empty, return 0
+    if (i == 0 && j == 0)
+        return 0;
+    // If s is empty, return the length of t
+    if (i == 0)
+        return j;
+    // If t is empty, return the length of s
+    if (j == 0)
+        return i;
+    // If there is a record, return it
+    if (mem[i][j] != -1)
+        return mem[i][j];
+    // If the two characters are equal, skip these two characters
+    if (s[i - 1] == t[j - 1])
+        return editDistanceDFSMem(s, t, mem, i - 1, j - 1);
+    // The minimum number of edits = the minimum number of edits from three operations (insert, remove, replace) + 1
+    int insert = editDistanceDFSMem(s, t, mem, i, j - 1);
+    int del = editDistanceDFSMem(s, t, mem, i - 1, j);
+    int replace = editDistanceDFSMem(s, t, mem, i - 1, j - 1);
+    // Record and return the minimum number of edits
+    mem[i][j] = min(min(insert, del), replace) + 1;
+    return mem[i][j];
+}
+
+/* Edit distance: Dynamic programming */
+int editDistanceDP(string s, string t) {
+    int n = s.length(), m = t.length();
+    vector<vector<int>> dp(n + 1, vector<int>(m + 1, 0));
+    // State transition: first row and first column
+    for (int i = 1; i <= n; i++) {
+        dp[i][0] = i;
+    }
+    for (int j = 1; j <= m; j++) {
+        dp[0][j] = j;
+    }
+    // State transition: the rest of the rows and columns
+    for (int i = 1; i <= n; i++) {
+        for (int j = 1; j <= m; j++) {
+            if (s[i - 1] == t[j - 1]) {
+                // If the two characters are equal, skip these two characters
+                dp[i][j] = dp[i - 1][j - 1];
+            } else {
+                // The minimum number of edits = the minimum number of edits from three operations (insert, remove, replace) + 1
+                dp[i][j] = min(min(dp[i][j - 1], dp[i - 1][j]), dp[i - 1][j - 1]) + 1;
+            }
+        }
+    }
+    return dp[n][m];
+}
+
+/* Edit distance: Space-optimized dynamic programming */
+int editDistanceDPComp(string s, string t) {
+    int n = s.length(), m = t.length();
+    vector<int> dp(m + 1, 0);
+    // State transition: first row
+    for (int j = 1; j <= m; j++) {
+        dp[j] = j;
+    }
+    // State transition: the rest of the rows
+    for (int i = 1; i <= n; i++) {
+        // State transition: first column
+        int leftup = dp[0]; // Temporarily store dp[i-1, j-1]
+        dp[0] = i;
+        // State transition: the rest of the columns
+        for (int j = 1; j <= m; j++) {
+            int temp = dp[j];
+            if (s[i - 1] == t[j - 1]) {
+                // If the two characters are equal, skip these two characters
+                dp[j] = leftup;
+            } else {
+                // The minimum number of edits = the minimum number of edits from three operations (insert, remove, replace) + 1
+                dp[j] = min(min(dp[j - 1], dp[j]), leftup) + 1;
+            }
+            leftup = temp; // Update for the next round of dp[i-1, j-1]
+        }
+    }
+    return dp[m];
+}
+
+/* Driver Code */
+int main() {
+    string s = "bag";
+    string t = "pack";
+    int n = s.length(), m = t.length();
+
+    // Brute force search
+    int res = editDistanceDFS(s, t, n, m);
+    cout << "Changing " << s << " to " << t << " requires a minimum of " << res << " edits.\n";
+
+    // Memoized search
+    vector<vector<int>> mem(n + 1, vector<int>(m + 1, -1));
+    res = editDistanceDFSMem(s, t, mem, n, m);
+    cout << "Changing " << s << " to " << t << " requires a minimum of " << res << " edits.\n";
+
+    // Dynamic programming
+    res = editDistanceDP(s, t);
+    cout << "Changing " << s << " to " << t << " requires a minimum of " << res << " edits.\n";
+
+    // Space-optimized dynamic programming
+    res = editDistanceDPComp(s, t);
+    cout << "Changing " << s << " to " << t << " requires a minimum of " << res << " edits.\n";
+
+    return 0;
+}