LintCode 888: Valid Word Square-优快云博客

本文探讨了如何检查一组字符串是否构成有效的单词方阵。单词方阵的有效性在于其每一行和每一列读起来是否完全相同。文章通过具体示例说明了判断标准，并提供了一种直接比较的方法来实现这一功能。

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Valid Word Square
中文English
Given a sequence of words, check whether it forms a valid word square.

A sequence of words forms a valid word square if the k^th row and column read the exact same string, where 0 ≤ k < max(numRows, numColumns).

Example
Example1

Input:
[
“abcd”,
“bnrt”,
“crmy”,
“dtye”
]
Output: true
Explanation:
The first row and first column both read “abcd”.
The second row and second column both read “bnrt”.
The third row and third column both read “crmy”.
The fourth row and fourth column both read “dtye”.

Therefore, it is a valid word square.
Example2

Input:
[
“abcd”,
“bnrt”,
“crm”,
“dt”
]
Output: true
Explanation:
The first row and first column both read “abcd”.
The second row and second column both read “bnrt”.
The third row and third column both read “crm”.
The fourth row and fourth column both read “dt”.

Therefore, it is a valid word square.
Example3

Input:
[
“ball”,
“area”,
“read”,
“lady”
]
Output: false
Explanation:
The third row reads “read” while the third column reads “lead”.

Therefore, it is NOT a valid word square.
Notice
The number of words given is at least 1 and does not exceed 500.
Word length will be at least 1 and does not exceed 500.
Each word contains only lowercase English alphabet a-z.

解法1：直接比较。
代码如下：

class Solution {
public:
    /**
     * @param words: a list of string
     * @return: a boolean
     */
    bool validWordSquare(vector<string> &words) {
        int m = words.size();
        if (m == 0) return true;
        
        int n = 0;
        for (int i = 0; i < m; ++i) {
            n = max(n, (int)words[i].size());
        }
        
        int i = 0, j = 0;
        
        for (i = 0; i < n; ++i) {
            string columString;
            for (j = 0; j < m; ++j) {
                if (words[j].size() >= i) columString += words[j][i];
            }
            if (columString != words[i]) return false;  
        }
        
        return true;
    }
};