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 RAnd 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"
.
class Solution {
public:
string convert(string s, int nRows) {
if(nRows==1||s.size()<1) // 注意边界条件,否则Memory Limit Exceed
return s;
string temp;
int t;
for(int i=1; i<=nRows; i++)
{
t=i-1;
if(i==1||i==nRows) // 首尾行规则与中间行不一样
{
while(t<s.size())
{
temp+=s[t];
t+=2*(nRows-1); // 首尾行规则
}
}
else
{
int j=1; // 区分每行元素的奇偶位,1表示偶数,0表示奇数位
while(t<s.size())
{
temp+=s[t];
if(j)
{
t+=2*(nRows-1)-2*(i-1); // 中间行偶数位规则
j=0;
}
else
{
t+=2*(i-1); // 中间行奇数为规则
j=1;
}
}
}
}
return temp;
}
};