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LeetCode/005. Longest Palindromic Substring.md

@@ -0,0 +1,31 @@
+class Solution {
+public:
+
+    string longestPalindrome(string s) {
+        if (s.length() < 1)    return "";
+    	int len1, len2, len,maxlen=0;
+    	int start = 0, end = 0;
+    	for (int i = 0; i < s.length(); i++) {
+    		len1 = expandAroundCenter(s, i, i);
+    		len2 = expandAroundCenter(s, i, i + 1);
+    		len = max(len1, len2);
+    		if (len > maxlen) maxlen = len;
+    		if (len > end - start) {
+    			start = i - (len - 1) / 2;
+    			end = i + len / 2;
+    			//cout << i << " " << start << " " << end << " " << len << endl;
+    		}
+    	}
+    	//cout  << start << " " << end << " " << len << endl;
+    	return s.substr(start, maxlen);//参考的solution  结果Java的substring是[start,end),C++的string是(start,length)因为随着遍历len可能还会变小,所以留存最大的len
+    }
+`private:`
+    `int expandAroundCenter(string s,int left,int right){`
+        `int L=left,R=right;`
+        `while(L>=0&&R<s.length()&&s[L]==s[R]){`
+            `L--;`
+            `R++;`
+        `}`
+        `return R-L-1;`
+    `}`
+`};`

LeetCode/709. To Lower Case.cpp

@@ -0,0 +1,10 @@
+class Solution {
+public:
+    //'a'-32='A'
+    string toLowerCase(string str) {
+    for (char& c : str) {
+        if (c >= 'A' && c <= 'Z') c += 32;
+    }
+    return str;
+    }
+};

LeetCode/804. Unique Morse Code Words.cpp

@@ -0,0 +1,14 @@
+class Solution {
+    string m[27]={".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--.."};
+public:
+    int uniqueMorseRepresentations(vector<string>& words) {
+        vector<string> d = {".-", "-...", "-.-.", "-..", ".", "..-.", "--.", "....", "..", ".---", "-.-", ".-..", "--",                              "-.", "---", ".--.", "--.-", ".-.", "...", "-", "..-", "...-", ".--", "-..-", "-.--", "--.."};
+        unordered_set<string> s;
+        for (auto word : words) {
+            string code;
+            for (auto c : word) code += d[c - 'a'];
+            s.insert(code);
+        }
+        return s.size();
+    }
+};

LeetCode/929. Unique Email Addresses.cpp

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+class Solution {
+public:
+    int numUniqueEmails(vector<string>& emails) {
+        unordered_set<string> s;     
+        for(auto email:emails){
+            string str;
+            auto it = email.begin();
+            for (; '@' != *it && '+' != *it; ++it) {
+                if ('.' != *it) {
+                    str += *it;
+                }
+            }
+            it=find(it, email.end(), '@');
+            str.append(it, email.end());
+            s.insert(str);
+        }
+        return s.size();
+    }
+};