Humming Distance and Repeated Substring Pattern

puzzles/interviews/training/hamming_distance.cpp

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+/*
+LeetCode
+461. Hamming Distance
+Easy
+
+The Hamming distance between two integers is the number of positions at which the corresponding bits are different.
+
+Given two integers x and y, calculate the Hamming distance.
+
+Note:
+0 ≤ x, y < 231.
+
+Example:
+
+Input: x = 1, y = 4
+
+Output: 2
+
+Explanation:
+1   (0 0 0 1)
+4   (0 1 0 0)
+       ↑   ↑
+
+The above arrows point to positions where the corresponding bits are different.
+*/
+class Solution {
+public:
+    int hammingDistance(int x, int y) {
+	    unsigned z = x ^ y;
+        z = (z & 0x55555555) + ((z >> 1) & 0x55555555);
+        z = (z & 0x33333333) + ((z >> 2) & 0x33333333);
+        z = (z & 0x0f0f0f0f) + ((z >> 4) & 0x0f0f0f0f);
+        z = (z & 0x00ff00ff) + ((z >> 8) & 0x00ff00ff);
+        z = (z & 0x0000ffff) + ((z >> 16) & 0x0000ffff);
+        return z;
+    }
+};

puzzles/interviews/training/repeated_substring_pattern.cpp

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+/*
+LeetCode
+459. Repeated Substring Pattern
+Easy
+
+Given a non-empty string check if it can be constructed by taking a substring of it and appending multiple copies of the substring together. You may assume the given string consists of lowercase English letters only and its length will not exceed 10000.
+
+
+
+Example 1:
+
+Input: "abab"
+Output: True
+Explanation: It's the substring "ab" twice.
+
+Example 2:
+
+Input: "aba"
+Output: False
+
+Example 3:
+
+Input: "abcabcabcabc"
+Output: True
+Explanation: It's the substring "abc" four times. (And the substring "abcabc" twice.)
+
+
+*/
+bool repeatedSubstringPattern(string s) {
+    size_t n = (s.size()+1)/2;
+    for (size_t i = 1; i <= n; ++i){
+        if (s[i] == s[0] && s.size() % i == 0){
+            size_t j = i;
+            for (; j < s.size() && s[j] == s[j-i]; ++j);
+            if (j == s.size()){
+                return true;
+            }
+        }
+    }
+    return false;
+}