From c1f249e103edb68c5ab31578610174612a6db815 Mon Sep 17 00:00:00 2001
From: anon <anon@anon.anon>
Date: Sun, 10 Mar 2024 15:57:35 +0100
Subject: [PATCH] Added levenshtein_dist_-_usage.cpp

---
 levenshtein_dist_-_usage.cpp | 74 ++++++++++++++++++++++++++++++++++++
 1 file changed, 74 insertions(+)
 create mode 100644 levenshtein_dist_-_usage.cpp

diff --git a/levenshtein_dist_-_usage.cpp b/levenshtein_dist_-_usage.cpp
new file mode 100644
index 0000000..304033d
--- /dev/null
+++ b/levenshtein_dist_-_usage.cpp
@@ -0,0 +1,74 @@
+// @BAKE g++ $@
+
+#include <string>
+#include <vector>
+#include <algorithm>
+
+using namespace std;
+
+// https://github.com/Meteorix/pylcs
+
+vector<string> utf8_split(const string &str){
+    vector<string> split;
+    int len = str.length();
+    int left = 0;
+    int right = 1;
+
+    for (int i = 0; i < len; i++){
+        if (right >= len || ((str[right] & 0xc0) != 0x80)){
+            string s = str.substr(left, right - left);
+            split.push_back(s);
+            // printf("%s %d %d\n", s.c_str(), left, right);
+            left = right;
+        }
+        right ++;
+    }
+    return split;
+}
+
+// https://github.com/schiffma/distlib
+int mini(int a, int b, int c){
+    return(min(a, min(b,c)));
+}
+
+int levenshtein_dist(const string &word1, const string &word2){
+    ///
+    ///  Please use lower-case strings
+    /// word1 : first word
+    /// word2 : second word
+    ///
+	
+    //int size1 = word1.size(), size2 = word2.size();
+
+    vector<string> word1_ = utf8_split(word1);
+    vector<string> word2_ = utf8_split(word2);
+    int size1 = word1_.size();
+    int size2 = word2_.size();		
+	
+    int suppr_dist, insert_dist, subs_dist;
+    int* dist = new int[(size1+1)*(size2+1)];
+
+    for(int i=0; i<size1+1; ++i)
+        dist[(size2+1)*i] = i;
+    for(int j=0; j<size2+1; ++j)
+        dist[j] = j;
+    for(int i=1; i<size1+1; ++i){
+        for(int j=1; j<size2+1; ++j){
+            suppr_dist = dist[(size2+1)*(i-1)+j] + 1;
+            insert_dist = dist[(size2+1)*i+j-1] + 1;
+            subs_dist = dist[(size2+1)*(i-1)+j-1];
+            if(word1_[i-1]!=word2_[j-1]){  // word indexes are implemented differently.
+                subs_dist += 1;
+            }
+            dist[(size2+1)*i+j] = mini(suppr_dist, insert_dist, subs_dist);
+        }
+    }
+    // --------------------------------------------------------
+    int res = dist[(size1+1)*(size2+1) - 1];
+    delete dist;
+    return(res);
+}
+
+signed main() {
+	return levenshtein_dist("ginger", "pilger");
+}