add code for 165. Compare Version Numbers

Author: PriyanshVerma

leetcode/cpp/string/165.cpp

@@ -0,0 +1,47 @@
+class Solution {
+public:
+    int compareVersion(string v1, string v2) {
+        int i1=0,i2=0;
+        while(i1<v1.length() && i2<v2.length()) {
+            int n1=-1, n2=-1;
+            
+            int p1 = (int)v1.find('.', i1);
+            if (p1!=string::npos) {
+                n1 = stoi(v1.substr(i1, p1-i1));
+                i1 = p1+1;
+            }
+            else {
+                n1 = stoi(v1.substr(i1));
+                i1 = v1.length();
+            }
+            
+            int p2 = (int)v2.find('.', i2);
+            if (p2!=string::npos) {
+                n2 = stoi(v2.substr(i2, p2-i2));
+                i2 = p2+1;
+            }
+            else {
+                n2 = stoi(v2.substr(i2));
+                i2 = v2.length();
+            }
+            
+            if (n1!= -1 && n2!= -1) {
+                if (n1>n2) return 1;
+                else if (n1<n2) return -1;
+            }
+        }
+        if (i1 == v1.length()) {
+            for(; i2<v2.length(); i2++) {
+                if (v2[i2] != '.' && v2[i2] != '0')
+                    return -1;
+            }
+        }  else if (i2 == v2.length()) {
+            for(; i1<v1.length(); i1++) {
+                if (v1[i1] != '.' && v1[i1] != '0')
+                    return 1;
+            }
+        }
+        return 0;
+        
+    }
+};