题解 | #矩阵最长递增路径#

public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     * 递增路径的最大长度
     * @param matrix int整型二维数组 描述矩阵的每个数
     * @return int整型
     */
    public int solve (int[][] matrix) {
        // write code here
        int rs = Integer.MIN_VALUE;
        for (int i = 0; i < matrix.length; i++) {
            for (int j = 0; j < matrix[0].length; j++) {
                rs = Math.max(rs, process(matrix, i, j, Integer.MIN_VALUE, 0));
            }
        }
        return rs;
    }
    
    public int process(int[][] matrix, int i, int j, int val, int rs) {
        if (i < 0 || i > matrix.length - 1 || j < 0 || j > matrix[0].length - 1 || matrix[i][j] == -1 || matrix[i][j] <= val) {
            return rs;
        }
        int tmp = matrix[i][j];
        matrix[i][j] = -1;
        rs += 1;
        int ur = process(matrix, i, j - 1, tmp, rs);
        int dr = process(matrix, i, j + 1, tmp, rs);
        int lr = process(matrix, i - 1, j, tmp, rs);
        int rr = process(matrix, i + 1, j, tmp, rs);
        matrix[i][j] = tmp;
        return Math.max(rr, Math.max(lr, Math.max(ur, dr)));
    }
}