Merge pull request #240 from Neha1204/master

Create Detect loop in LinkedList.cpp

Detect loop in LinkedList.cpp

@@ -0,0 +1,28 @@
+/**
+ * Definition for singly-linked list.
+ * struct ListNode {
+ *     int val;
+ *     ListNode *next;
+ *     ListNode(int x) : val(x), next(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    bool hasCycle(ListNode *head) {
+
+        if(head== NULL || head->next == NULL) return false;
+
+        ListNode *slow= head->next, *fast= slow->next;
+
+        while(slow!= NULL && fast != NULL && slow!= fast){
+            slow= slow->next;
+            fast= fast->next;
+            if(fast!=NULL) fast=fast->next;
+        }
+
+        if(slow==NULL || fast ==NULL) return false;
+
+        return true;
+
+    }
+};

Numeric string to int

@@ -0,0 +1,13 @@
+int StringToInt(string s){
+    int ans = 0, i=0;
+
+    if(s.size()==0) return 0;
+    if(s[0] == '-') i++;
+
+    for( i; i<s.size(); i++){
+        ans = ans*10 + (s[i]-48);
+    }
+
+    if(s[0] == '-') ans = ans*(-1);
+    return ans;
+}