leetcode: Longest Common Prefix

Write a function to find the longest common prefix string amongst an array of strings.

思路

两个两个的比较，然后递归。

class Solution {
public:
    string longestCommonPrefix(vector<string> &strs) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
		if(strs.size()==0) return "";
		if(strs.size()==1) return strs[0];
		vector<string> rstrs;
		char *buff = new char[strs[0].length()+1];
		int mleng=strs[0].length();
        for(int i=0;i<strs.size();i+=2)
		{
			if(i+1<strs.size())
			{
				mleng=minnum(strs[i].length(),strs[i+1].length(),mleng);
				memset(buff,0,strs[0].length()+1);
				for(int j=0;j<mleng;j++)
				{
					if(strs[i][j]==strs[i+1][j])
						buff[j]=strs[i][j];
					else
						break;
				}
				string tmp(buff);
				rstrs.push_back(tmp);
			}
			else
			{
				string tmp(strs[i]);
				rstrs.push_back(tmp);
			}
		}
		delete[] buff;
		return longestCommonPrefix(rstrs);
    }

	inline int minnum(int a, int b, int c)
	{
		int tmp=a<b?a:b;
		return tmp<c?tmp:c;
	}
};