Merge pull request #339 from SaurusXI/master

Added commented solution to Leetcode problem 476

leetcode/README.md

@@ -49,6 +49,7 @@ LeetCode
 |404|[Sum of Left Leaves](https://leetcode.com/problems/sum-of-left-leaves/) | [C](./src/404.c)|Easy|
 |442|[Find All Duplicates in an Array](https://leetcode.com/problems/find-all-duplicates-in-an-array/) | [C](./src/442.c)|Medium|
 |461|[Hamming Distance](https://leetcode.com/problems/hamming-distance/) | [C](./src/461.c) |Easy|
+|476|[Number Complement](https://leetcode.com/problems/number-complement/) | [C](./src/476.c)|Easy|
 |509|[Fibonacci Number](https://leetcode.com/problems/fibonacci-number/) | [C](./src/509.c)|Easy|
 |520|[Detect Capital](https://leetcode.com/problems/detect-capital/) | [C](./src/520.c)|Easy|
 |561|[Array Partition I](https://leetcode.com/problems/array-partition-i/) | [C](./src/561.c)|Easy|

leetcode/src/476.c

@@ -0,0 +1,15 @@
+int findComplement(int num) {
+    int TotalBits = 0;
+    int temp = num;
+    while(temp) {               //To find position of MSB in given num. Since num is represented as a standard size in memory, we cannot rely on size
+                                //for that information.
+        TotalBits++;            //increment TotalBits till temp becomes 0
+        temp >>= 1;             //shift temp right by 1 bit every iteration; temp loses 1 bit to underflow every iteration till it becomes 0
+    }
+    int i, flipNumber = 1;      //Eg: 1's complement of 101(binary) can be found as 101^111 (XOR with 111 flips all bits that are 1 to 0 and flips 0 to 1)
+    for(i = 1; i < TotalBits; i++) {
+        flipNumber += UINT32_C(1) << i; //Note the use of unsigned int to facilitate left shift more than 31 times, if needed
+    }
+    num = num^flipNumber;
+    return num;
+}