From cd679fd4613d8fb3c9745bdd666520ba7413b276 Mon Sep 17 00:00:00 2001
From: Paul Fugmann <paul.fugmann@mni.thm.de>
Date: Sat, 26 Oct 2019 16:04:24 +0200
Subject: [PATCH] Add leetcode String to Integer (atoi) (8.c) and Integer to
 Roman (12.c)

---
 leetcode/README.md |   2 +
 leetcode/src/12.c  | 164 +++++++++++++++++++++++++++++++++++++++++++++
 leetcode/src/8.c   |  60 +++++++++++++++++
 3 files changed, 226 insertions(+)
 create mode 100644 leetcode/src/12.c
 create mode 100644 leetcode/src/8.c

diff --git a/leetcode/README.md b/leetcode/README.md
index fe701f66..015f1ae5 100644
--- a/leetcode/README.md
+++ b/leetcode/README.md
@@ -10,6 +10,8 @@ LeetCode
 |2|[Add Two Numbers](https://leetcode.com/problems/add-two-numbers/) | [C](./src/2.c)|Medium|
 |3|[Longest Substring Without Repeating Characters](https://leetcode.com/problems/longest-substring-without-repeating-characters/) | [C](./src/3.c)|Medium|
 |4|[Median of Two Sorted Arrays](https://leetcode.com/problems/median-of-two-sorted-arrays/) | [C](./src/4.c)|Hard|
+|8|[String to Integer (atoi)](https://leetcode.com/problems/string-to-integer-atoi) | [C](./src/8.c)|Medium|
+|12|[Integer to Roman](https://leetcode.com/problems/integer-to-roman) | [C](./src/12.c)|Medium|
 |20|[Valid Parentheses](https://leetcode.com/problems/valid-parentheses/) | [C](./src/20.c)|Easy|
 |21|[Merge Two Sorted Lists](https://leetcode.com/problems/merge-two-sorted-lists/) | [C](./src/21.c)|Easy|
 |24|[Swap Nodes in Pairs](https://leetcode.com/problems/swap-nodes-in-pairs/) | [C](./src/24.c)|Medium|
diff --git a/leetcode/src/12.c b/leetcode/src/12.c
new file mode 100644
index 00000000..ec33b979
--- /dev/null
+++ b/leetcode/src/12.c
@@ -0,0 +1,164 @@
+char *getOne(char c){
+    switch (c) {
+        case '9':
+            return "IX";
+
+        case '8':
+            return "VIII";
+
+        case '7':
+            return "VII";
+
+        case '6':
+            return "VI";
+
+        case '5':
+            return "V";
+
+        case '4':
+            return "IV";
+
+        case '3':
+            return "III";
+
+        case '2':
+            return "II";            
+
+        case '1':
+            return "I";
+
+        case '0':
+            return "";
+
+        default:
+            return NULL;
+    }
+}
+
+char *getTen(char c){
+    switch (c) {
+        case '9':
+            return "XC";
+
+        case '8':
+            return "LXXX";
+
+        case '7':
+            return "LXX";
+
+        case '6':
+            return "LX";
+
+        case '5':
+            return "L";
+
+        case '4':
+            return "XL";
+
+        case '3':
+            return "XXX";
+
+        case '2':
+            return "XX";            
+
+        case '1':
+            return "X";
+
+        case '0':
+            return "";
+
+        default:
+            return NULL;
+    }
+
+}
+
+char *getHundred(char c){
+    switch (c) {
+        case '9':
+            return "CM";
+
+        case '8':
+            return "DCCC";
+
+        case '7':
+            return "DCC";
+
+        case '6':
+            return "DC";
+
+        case '5':
+            return "D";
+
+        case '4':
+            return "CD";
+
+        case '3':
+            return "CCC";
+
+        case '2':
+            return "CC";            
+
+        case '1':
+            return "C";
+
+        case '0':
+            return "";
+            
+        default:
+            return NULL;
+    }
+}
+
+char *getThousand(char c){
+    switch (c) {
+        case '3':
+            return "MMM";
+
+        case '2':
+            return "MM";            
+
+        case '1':
+            return "M";
+            
+        default:
+            return NULL;
+    }
+}
+
+
+
+
+char * intToRoman(int num){
+    int length;
+    char number[5];
+    char *s = malloc(16*sizeof(char));
+    
+    sprintf(number, "%i", num); 
+    
+    length = strlen(number);
+
+    switch (length){
+        case 4:
+            sprintf(s,"%s%s%s%s", getThousand(number[0]), getHundred(number[1]), getTen(number[2]), getOne(number[3]));
+            break;
+
+        case 3:
+            sprintf(s,"%s%s%s", getHundred(number[0]), getTen(number[1]), getOne(number[2]));
+            
+            break;
+
+        case 2:
+            sprintf(s,"%s%s", getTen(number[0]), getOne(number[1]));
+            
+            break;
+
+        case 1: 
+            s = getOne(number[0]);
+            break;
+
+        default:
+            break;
+    }
+    return s;
+}
diff --git a/leetcode/src/8.c b/leetcode/src/8.c
new file mode 100644
index 00000000..91c4d736
--- /dev/null
+++ b/leetcode/src/8.c
@@ -0,0 +1,60 @@
+int myAtoi(char * str){
+    int minusFlag = 0;
+    int length = strlen(str);
+    long int result = 0;
+    char numberBuffer[11];
+    int counter = 0;
+    while(str[counter] == ' '){
+        counter++;
+    }
+    str = &str[counter];
+    counter = 0;
+
+   
+    for(int i=0; i<length; i++){
+        if(i == 0) {
+            if(str[0] == '-'){
+                minusFlag = 1;
+                i++;
+            } else if(str[0] == '+'){
+                i++;
+            }
+        }
+        if(counter>10){
+            if(minusFlag){
+                return __INT_MAX__*-1-1;
+            } else {
+                return __INT_MAX__;
+            }
+        }
+
+        if(str[i] < '0' || str[i] > '9'){
+            break;
+        }
+        if(counter == 0 && str[i] == '0'){
+            continue;
+        }
+        
+        numberBuffer[counter]= str[i];
+        counter++;
+    }
+
+    int i = 0;
+    while(counter > 0) {
+        if(minusFlag){
+            result -= (numberBuffer[i] - '0')*pow(10.0, counter-1);
+        }else{
+            result += (numberBuffer[i] - '0')*pow(10.0, counter-1);
+        }
+        i++;
+        counter--;
+    }
+    
+    if(result > __INT_MAX__){
+        return __INT_MAX__;
+    } else if(result < __INT_MAX__*-1-1){
+        return __INT_MAX__*-1-1;
+    }
+    return result;
+}
+