added the levenshtein distance algorithm

Author: Barbu Paul - Gheorghe

l.in

@@ -0,0 +1 @@
+ioana dania

levenshtein_distance.c

@@ -0,0 +1,61 @@
+/**
+ * Calculate the levenshtein distance between two strings
+ */
+#include <stdio.h>
+#include <string.h>
+
+int d[100][100]; //change this if one of the strings is longer than 100 chars
+
+int minimum_of_three(int x, int y, int z){
+    if(x<y){
+        y = x;
+    }
+
+    if(y<z){
+        z = y;
+    }
+
+    return z;
+}
+
+int levenshtein_distance(char* a, char* b){
+    int length_a = strlen(a), length_b = strlen(b);
+
+    for(int i=0; i<length_a; i++){
+        d[i][0] = i;
+    }
+
+    for(int i=0; i<length_b; i++){
+        d[0][i] = i;
+    }
+
+    for(int i=1; i<length_a; i++){
+        for(int j=1; j<length_b; j++){
+            if(a[i] == b[j]){
+                d[i][j] = d[i-1][j-1];
+            }
+            else{
+                d[i][j] = 1 + minimum_of_three(d[i-1][j], d[i][j-1], d[i-1][j-1]);
+            }
+        }
+    }
+
+    return d[length_a-1][length_b-1];
+}
+
+int main(){
+    char a[100], b[100], pa[100] = " ", pb[100] = " ";
+    FILE *f;
+
+    f = fopen("l.in", "r");
+
+    fscanf(f, "%s %s", a, b);
+
+    //need this in order to have the same starting point in both strings
+    strcat(pa, a);
+    strcat(pb, b);
+
+    printf("%d\n",levenshtein_distance(pa, pb));
+
+    fclose(f);
+}