Que65.java

/**
 * @author: hyl
 * @date: 2019/08/17
 **/
public class Que65 {


    public boolean hasPath(char[] matrix, int rows, int cols, char[] str) {


        int[] flag = new int[matrix.length];

        //从任一起点出发
        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < cols; j++) {
                if (helper(matrix , rows , cols , i , j , str , 0, flag)){
                    return true;
                }
            }
        }

        return false;

    }

    private boolean helper(char[] matrix, int rows, int cols, int i, int j, char[] str, int k, int[] flag) {

        //计算出在matrix中的位置
        int index = i * cols + j;
        if (i < 0 || i >= rows || j < 0 || j >= cols || matrix[index] != str[k] || flag[index] == 1){
            return false;
        }

        if(k == str.length - 1){
            return true;
        }

        flag[index] = 1;

        if (helper(matrix , rows , cols , i - 1 , j , str , k + 1, flag)
             ||helper(matrix , rows , cols , i + 1 , j , str , k + 1, flag)
             ||helper(matrix , rows , cols , i , j + 1 , str , k + 1, flag)
              ||helper(matrix , rows , cols , i , j - 1 , str , k + 1, flag)){
            return true;
        }

        flag[index] = 0;


        return false;
    }

}