Description
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 s, int numRows);
Example 1:
Input: s = "PAYPALISHIRING", numRows = 3
Output: "PAHNAPLSIIGYIR"
Example 2:
Input: s = "PAYPALISHIRING", numRows = 4
Output: "PINALSIGYAHRPI"
Explanation:
P I N
A L S I G
Y A H R
P I
Example 3:
Input: s = "A", numRows = 1
Output: "A"
Constraints:
1 <= s.length <= 1000sconsists of English letters (lower-case and upper-case),','and'.'.1 <= numRows <= 1000
Solution
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class Solution {
public:
string convert(string s, int numRows) {
if (numRows == 1) {
return s;
}
string str[numRows];
int delta = 1, str_idx = 0;
for (int i = 0; i < s.size(); i++) {
str[str_idx] += s[i];
if (str_idx == 0) {
delta = 1;
} else if (str_idx == numRows - 1) {
delta = -1;
}
str_idx += delta;
}
string ret;
for (int i = 0; i < numRows; i++) {
ret += str[i];
}
return ret;
}
};
Runtime: 12 ms, faster than 65.95% of C++ online submissions for ZigZag Conversion.
Memory Usage: 8.3 MB, less than 80.44% of C++ online submissions for ZigZag Conversion.
