Leetcode日记（6）---ZigZag Conversion

//通过的代码
class Solution {
public:
string convert(string s, int numRows) {
if(numRows<2 || s.size()<=numRows) return s;
string res(s.size(),0);
char *p=&res[0];
for(int i=0, j,k, step=(numRows-1)*2;i<numRows;++i) {
if(i==0 || i==numRows-1)
for(j=i;j<s.size();j+=step) *p++=s[j];
else
for(j=i, k=i<<1;j<s.size();k=step-k,j+=k) *p++=s[j];
}
return res;
}
};

public class Solution {
public String convert(String s, int nRows) {
int len = s.length();
if (len == 0 || nRows <= 1) return s;

String[] ans = new String[nRows];
Arrays.fill(ans, "");
int row = 0, delta = 1;
for (int i = 0; i < len; i++) {
ans[row] += s.charAt(i);
row += delta;
if (row >= nRows) {
row = nRows-2;
delta = -1;
}
if (row < 0) {
row = 1;
delta = 1;
}
}

String ret = "";
for (int i = 0; i < nRows; i++) {
ret += ans[i];
}
return ret;
}
}