first commit to LeetCode Repo.

Author: Badhansen

344. Reverse String.cpp

@@ -0,0 +1,44 @@
+// Solution one
+class Solution {
+public:
+    void reverseString(vector<char>& s) {
+
+
+        rec(s, 0, s.size() - 1);
+        /*
+        reverse(s.begin(), s.end());
+        for(int i=0; i<s.size(); i++){
+            if(i == 0) cout << "[\""  << s[i] << '"' << ",";
+            else if(i == s.size()-1){
+                cout << '"' << s[i] << '"' << "]" << endl;
+            }
+            else cout << '"' << s[i] << '"' << ",";
+        }
+        */
+
+    }
+    void rec(vector<char> &v, int st, int ed){
+        if(st >= ed){
+            return;
+        }
+        rec(v, st + 1, ed - 1);
+        swap(v[st], v[ed]);
+    }
+};
+
+// Solution Two
+class Solution {
+public:
+    void reverseString(vector<char>& s) {
+
+        reverse(s.begin(), s.end());
+        for(int i=0; i<s.size(); i++){
+            if(i == 0) cout << "[\""  << s[i] << '"' << ",";
+            else if(i == s.size()-1){
+                cout << '"' << s[i] << '"' << "]" << endl;
+            }
+            else cout << '"' << s[i] << '"' << ",";
+        }
+
+    }
+};

415. Add Strings.cpp

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+class Solution {
+public:
+    string addStrings(string num1, string num2) {
+        int s1 = num1.size(), s2 = num2.size();
+        if(s1 < s2){
+            while(s1 < s2){
+                num1 = "0" + num1;
+                s1++;
+            }
+        }
+        if(s2 < s1){
+            while(s2 < s1){
+                num2 = "0" + num2;
+                s2++;
+            }
+        }
+        int carry = 0, a, b;
+        string sum = "";
+        for(int i=s1 - 1; i>=0; i--){
+            a = num1[i] - '0';
+            b = num2[i] - '0';
+            if(carry + a + b >= 10){
+                carry += a + b;
+                sum += char((carry % 10) + '0');
+                carry /= 10;
+            }
+            else{
+                carry += a + b;
+                sum += char((carry % 10) + '0');
+                carry /= 10;
+            }
+        }
+        while(carry){
+            sum += char((carry % 10) + '0');
+            carry /= 10;
+        }
+        reverse(sum.begin(), sum.end());
+        return sum;
+    }
+};

557. Reverse Words in a String III.cpp

@@ -0,0 +1,15 @@
+class Solution {
+public:
+    string reverseWords(string s) {
+        stringstream ss(s);
+        string words;
+        string str = "";
+        while(ss >> words){
+            reverse(words.begin(), words.end());
+            str += words;
+            str += " ";
+        }
+        str.pop_back();
+        return str;
+    }
+};

657. Robot Return to Origin.cpp

@@ -0,0 +1,15 @@
+class Solution {
+public:
+    bool judgeCircle(string moves) {
+        int r, c;
+        r = c = 0;
+        for(int i=0; i<moves.size(); i++){
+            if(moves[i] == 'U') c++;
+            else if(moves[i] == 'D') c--;
+            else if(moves[i] == 'L') r++;
+            else r--;
+        }
+        if(r == 0 && c == 0) return true;
+        return false;
+    }
+};

709. To Lower Case.cpp

@@ -0,0 +1,9 @@
+class Solution {
+public:
+    string toLowerCase(string str) {
+        for(int i=0; i<str.size(); i++){
+            str[i] = tolower(str[i]);
+        }
+        return str;
+    }
+};

804. Unique Morse Code Words.cpp

@@ -0,0 +1,15 @@
+class Solution {
+public:
+    int uniqueMorseRepresentations(vector<string>& words) {
+        vector<string> s = {".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--.."};
+        set<string> st;
+        for(int i=0; i<words.size(); i++){
+            string str = "";
+            for(int j=0; j<words[i].size(); j++){
+                str += s[words[i][j] - 'a'];
+            }
+            st.insert(str);
+        }
+        return st.size();
+    }
+};

929. Unique Email Addresses.cpp

@@ -0,0 +1,33 @@
+class Solution {
+public:
+    int numUniqueEmails(vector<string>& emails) {
+        set<string> st;
+        for(int i=0; i<emails.size(); i++){
+            string str = "";
+            bool plus = false, atThe = false;
+            for(int j=0; j<emails[i].size(); j++){
+                if(!plus){
+                    // if plus is not found yet
+                    if(emails[i][j] == '.' && !atThe) continue;
+                    else{
+                        if(emails[i][j] == '+' && !atThe){
+                            plus = true;
+                        }
+                        else str += emails[i][j];
+                    }
+                }
+                else{
+                    // if plus is found then find the @
+                    if(emails[i][j] == '@'){
+                        plus = false;
+                        atThe = true;
+                        str += '@';
+                    }
+                }
+            }
+            //cout << str << endl;
+            st.insert(str);
+        }
+        return st.size();
+    }
+};