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【LeetCode with Python】 6. ZigZag Conversion

题目

原题页面:https://leetcode.com/problems/zigzag-conversion/
本文地址:</zigzag-conversion/>
题目类型:String
难度评价:Easy

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)
P---A---H---N
A-P-L-S-I-I-G
Y---I---R

And then read line by line: "PAHNAPLSIIGYIR"
Write the code that will take a string and make this conversion given a number of rows:
string convert(string text, int nRows);
convert("PAYPALISHIRING", 3) should return "PAHNAPLSIIGYIR".


分析

下标计算处理,控制好循环条件,下标不要越界即可。


代码

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class Solution:
# @return a string
def convert(self, s, nRows):
if 1 == nRows:
return s

len_s = len(s)
piece_len = 2 * (nRows - 1)

result = ""
index = 0
while index < len_s:
result += s[index]
index += piece_len
for m in range(1, nRows - 1):
index = m
while index < len_s:
result += s[index]
right_index = index + (nRows - m - 1) * 2
if right_index < len_s:
result += s[right_index]
index += piece_len
index = nRows - 1
while index < len_s:
result += s[index]
index += piece_len

return result