ZigZag Conversion - Javascript

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".

Subscribe to see which companies asked this question

Tag

String

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------

/**
 * @param {string} s
 * @param {number} numRows
 * @return {string}
 */
var convert = function(s, numRows) {
    if(numRows === 1) {
        return s;
    }
    
    var diff = 2*numRows-2;
    var ret = "";
    for(var i=0;i<numRows;i++) {
        for(var j=i;j<s.length;j+=diff) {
            ret += s[j];
            if(i!== 0 && i!== (numRows-1)) {
                var temp = j + diff - 2 * i;
                if (temp < s.length) {
                    ret += s[temp];
                }
            }
        }
    }
    
    return ret;
};