关于算法:6-Z-字形变换

public class ZConvert {

public String convert(String s, int numRows) {    int n = s.length(), r = numRows;    if (r == 1 || r >= n) {        return s;    }    StringBuffer[] mat = new StringBuffer[r];    for (int i = 0; i < r; ++i) {        mat[i] = new StringBuffer();    }    //一个周期元素个数 = numRows + (numRows - 2);    int t = 2 * (numRows - 1);    //指标字符串共须要 (n/t) + 1 个周期    int tCount = (n/t) + 1;    //以后遍历的下标    int index = 0;    for (int i = 0; i < tCount; i++) {        //以后周期下标 <= 字符串长度        if (index+t <= n) {            //截取以后周期的字符            processT(s.substring(index, index+t), numRows, t, mat);        } else {            processT(s.substring(index, n), numRows, t, mat);        }        index += t;    }    StringBuffer ans = new StringBuffer();    for (StringBuffer row : mat) {        ans.append(row);    }    return ans.toString();}public void processT(String sSub, int numRows, int t, StringBuffer[] mat) {    int count = t;    //子串的长度 小于 周期    if (sSub.length() < t) {        //从新赋值子串遍历个数        count = sSub.length();    }    for(int i = 0; i < count; i++){        char ele = sSub.charAt(i);        //遍历次数 小于 t-(numRows-2)        if (i < t-(numRows-2)) {            //间接追加以后字符            mat[i].append(ele);        }        if (i >= t-(numRows-2)) {            //遍历次数 大于等于 t-(numRows-2)            int matIndex = numRows-(i+1)%numRows-1;            // mat的下标 = numRows-(i+1)%numRows-1            mat[matIndex].append(ele);        }    }}public static void main(String[] args) {    String s = "PAYPALISHIRING";    String target = "PAHNAPLSIIGYIR";    String result = new ZConvert().convert(s, 3);    Assert.check(target.equals(result), "失败");    System.out.println("胜利！");}

}