[LeetCode] Longest Common Prefix

Longest Common Prefix

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

解题思路：

注意string类的append和push_back方法的使用。

1. 先求两个字符串的前缀，在求此前缀与剩下的字符串的前缀。代码如下：

class Solution {
public:
	string longestCommonPrefix(vector<string> &strs){
		string result = "";
		int count = strs.size();
		if (count == 0){
			return "";
		}
		if (count == 1){
			return strs[0];
		}
		result = commonPrefix(strs[0], strs[1]);
		for (int i = 2; i < count; i++){
			if (result == ""){
				break;
			}
			result = commonPrefix(result, strs[i]);
		}
		
		return result;
	}
private:
	string commonPrefix(string& s1, string& s2){
		int len1 = s1.length();
		int len2 = s2.length();
		int len = len1 < len2 ? len1 : len2;
		string result = "";
		for (int i = 0; i < len; i++){
			if (s1[i] == s2[i]){
				result.append(1, s1[i]);
			}
			else{
				break;
			}
		}
		return result;
	}
};

class Solution {
public:
	string longestCommonPrefix(vector<string> &strs){
		string result = "";
		int count = strs.size();
		if (count == 0){
			return "";
		}
		int minLen = strs[0].length();
		for (int i = 1; i < count; i++){
			if (minLen > strs[i].length()){
				minLen = strs[i].length();
			}
		}
		for (int i = 0; i < minLen; i++){
			char c = strs[0][i];
			int j = 1;
			for (; j < count; j++){
				if (strs[j][i] != c){
					break;
				}
			}
			if (j == count){
				result.append(1, c);
			}else{
			    break;
			}
		}
		
		return result;
	}
};

[LeetCode] Longest Common Prefix

原文：http://blog.csdn.net/kangrydotnet/article/details/44622125