- Leetcode 58. Length of Last Word
- Leetcode 14. Longest Common Prefix
- Leetcode 151. Reverse Words in a String
- Leetcode 179. Largest Number
String Series
Leetcode 58. Length of Last Word
Given a string s consists of upper/lower-case alphabets and empty space characters ‘ ‘, return the length of last word in the string. If the last word does not exist, return 0.
Note: A word is defined as a character sequence consists of non-space characters only.
For example, Given s = “Hello World”, return 5.
class Solution {
public:
int lengthOfLastWord(string s) {
int len = 0;
if (s.empty()) return 0;
const int n = s.size();
for (int i=0; i<n; i++) {
if (s[i] != ' ') len++;
else {
while (i<n && s[i]==' ') i++;
if (i<n && s[i]!=' ') len = 1;
}
}
return len;
}
};
Leetcode 14. Longest Common Prefix
Write a function to find the longest common prefix string amongst an array of strings.
class Solution {
public:
string longestCommonPrefix(vector<string>& strs) {
string res;
if (strs.empty()) return res;
for (int i=0; i<strs[0].size(); i++) {
char temp = strs[0][i];
for (int j=1; j<strs.size(); j++) {
if (i>=strs[j].size() || strs[j][i]!=temp)
return res;
}
res+=temp;
}
return res;
}
};
Leetcode 151. Reverse Words in a String
class Solution {
public:
void reverseWords(string &s) {
istringstream input(s);
string res, temp;
while(input>>temp)
res = " "+ temp + res;
s = res.empty()?res: res.substr(1);
}
};
Leetcode 179. Largest Number
Given a list of non negative integers, arrange them such that they form the largest number.
For example, given [3, 30, 34, 5, 9], the largest formed number is 9534330.
Note: The result may be very large, so you need to return a string instead of an integer.
class Solution {
public:
string largestNumber(vector<int>& nums) {
const int n = nums.size();
vector<string> str(n);
for (int i=0; i<n; i++)
str[i] = to_string(nums[i]);
sort(str.begin(), str.end(), [](string &i, string &j){return i+j>j+i;});
string res;
for (string s:str) res+=s;
return res[0]=='0'?"0":res;
}
};
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