Merge pull request #1717 from gourgopal/patch-2

Update 0014-longest-common-prefix.cpp

Author: caba5

cpp/0014-longest-common-prefix.cpp

@@ -1,59 +1,28 @@
 class Solution {
 public:
-  vector<vector<int>> res;
-  
-  vector<vector<int>> fourSum(vector<int>& nums, int target) {
-    
-      if(nums.size() < 4) return res;
-    
-      vector<int>quad;
-      sort(nums.begin() , nums.end());
-      kSum(0,4,target,nums,quad);
-      return res;
-    }
-  
-  
-  void kSum (int index , int k , long long target, vector<int> nums , vector<int>&q)
-  {
-    
-    if(k == 2)
-    {
-      twoSum(index , target, q , nums);
-      return;
-    }
- 
-    for(int i = index ; i < nums.size() - k + 1; i++)
-    {
-      if(i > index && nums[i] == nums[i-1]) continue;
-      q.push_back(nums[i]);
-      kSum(i+1 , k-1 , target-nums[i] , nums , q);
-      q.pop_back();
-    }      
-
-  }
-  
-  void twoSum (int start,long long target,vector<int>&ans,vector<int>& nums)
-  {
-    int lo = start;
-    int hi = nums.size()-1;
-    
-    while(lo < hi)
-    {
-      int sum = nums[lo]+nums[hi];
-      if(sum > target) hi--;
-      else if (sum < target) lo++;
-      
-      else 
-      {
-        ans.insert(ans.end() , {nums[lo] , nums[hi]});
-        res.push_back(ans);
+    string longestCommonPrefix(vector<string>& strs) {
+        string result = strs[0];
+        int charIndex = 0;
 
-        ans.pop_back();
-        ans.pop_back();
-        
-        lo++;
-        while (lo < hi && nums[lo] == nums[lo - 1]) lo++;
-      }
-    }    
-  }
+        //finding minimum string length  - that could be max common prefix
+        long maxCharIndex = strs[0].length();
+        for (int i = 1; i < strs.size(); ++i) {
+            if (strs[i].length() < maxCharIndex) {
+                maxCharIndex = strs[i].length();
+            }
+        }
+
+        while (charIndex < maxCharIndex) {
+            char prevChar = strs[0][charIndex];
+            for (int i = 1; i < strs.size(); ++i) {
+                if (prevChar == strs[i][charIndex]) {
+                    continue;
+                }
+                return result.substr(0, charIndex);
+            }
+            ++charIndex;
+            result += prevChar;
+        }
+        return result.substr(0, charIndex);
+    }
 };