每日算法

LeetCode_6_ZigZag Conversion

LeetCode 6.ZigZag Conversion

问题描述:

The string “PAYPALISHIRING” is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font for better legibility)
Alt text

And then read line by line: “PAHNAPLSIIGYIR”

Write the code that will take a string and make this conversion given a number of rows:

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string convert(string s, int numRows);

样例如下

Example 1:

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Input: s = "PAYPALISHIRING", numRows = 3
Output: "PAHNAPLSIIGYIR"

Example 2:

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Input: s = "PAYPALISHIRING", numRows = 4
Output: "PINALSIGYAHRPI"

Explanation:
Alt text

解题思路:

弄一个numRows * s.length()的数组,便利s,按规律插入就行了

代码如下:
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class Solution {
public:
    string convert(string s, int numRows) {
        int len = s.length();
        vector<vector<char> > ss(numRows,vector<char>(len, '0'));
        int i, j;
        if(len == 0) return "";
        if(numRows == 1) return s;
        ss[0][0] = s[0];
        int count = 0;
        bool spe = false;
        int x = 0;
        int y = 0;
        for(i = 1; i < len; i++) {
            if(!spe) {
                x++;
                ss[x][y] = s[i];
                //cout << x << " " << y << " " << ss[x][y] << endl;
            } else {
                x--, y++;
                ss[x][y] = s[i];
                //cout << x << " " << y <<" " << ss[x][y] << endl;
            }
            count++;
            if(count == numRows-1) {
                count = 0;
                spe = !spe;
            }
        }
        string re;
        for(i = 0; i < numRows; i++) {
            for(j = 0; j <= y; j++) {
                if(ss[i][j] != '0') re.push_back(ss[i][j]); 
                //cout << ss[i][j ] << endl;
            }
        }
        return re;
    }
};