Question

我有一组递归的if语句，它们是用Java编写的，我尝试将其用于Clojure语法，但出现ArrayOutOfBound错误。该函数接受row = 0，col = 0和多维字符数组。

这是Java代码：

public static boolean solveMaze(int r, int c, char[][] maze) {

    //check for boundaries
    if(r < 0 || c < 0 || r >= maze.length || c >= maze[0].length)
        return false;
    //base case, did i reach the finish?
    if(maze[r][c] == '@')
        return true;
    //check if I'm at a valid point
    if(maze[r][c] != '-')
    //I have hit a wall, not a valid solution
        return false;
    //must be on a path, may be the right path
    //leave a bread crumb
    maze[r][c] = '!';
    //check above
    if(solveMaze(r-1,c, maze)) {

        maze[r][c] = '+';
        return true;
    }
    //check below
    if(solveMaze(r+1,c, maze)) {

        maze[r][c] = '+';
        return true;
    }
    //check left
    if(solveMaze(r,c-1, maze)) {

        maze[r][c] = '+';
        return true;
    }
    //check right
    if(solveMaze(r,c+1, maze)) {

        maze[r][c] = '+';
        return true;
    }
    //if I reach this point...
    return false;
}

这是我在clojure中提供的代码超出范围错误的代码：

    (defn solveMaze [r c m]
    (def tt true)
    ;(def che false)

    ;check to verify boundaries
    (if (or (or (or (< r 0) (< c 0)) (>= r (count m))) (>= c (count (str (m 0)))))
        false
        true
    )
    ;Check to know if the @ symbol has been found
    (if (= (get-in m[r c]) "@")
        true
        false
    )
    ;Checking if current index is a valid one
    (if (not= (get-in m[r c]) "-")
        ;Wall hit
        false
        true
    )
    ;found a path, leave a breadcrumb
    (def temp_map (assoc-in m[r c] "!"))
    ;Check North
    (if (= (solveMaze (dec r) c m) true)
        (def temp_map (assoc-in m [r c] "+"))
        true   
        ;false
    )
    ;Check South
    (if (= (solveMaze (inc r) c m) true)
        (def temp_map (assoc-in m[r c] "+"))
        true
        ;false
    )
    ;Check East
    (if (= (solveMaze r (dec c) m) true)
        (def temp_map (assoc-in m[r c] "+"))
        true
        ;false
    )
    ;Check West
    (if (= (solveMaze r (inc c) m) true)
        (def temp_map (assoc-in m[r c] "+"))
        true
        ;false
    )
    ;If code gets here
    (= tt false)

）

请问我在做错什么吗？？？我已经尝试过使用clojure的多个if构造，但是它不起作用。

Answer 1

您需要阅读Clojure的基础知识：

Brave Clojure（在线和预订）
Getting Clojure书
Clojure CheatSheet书

Answer 2

使用条件代替if来解决这个问题。现在，代码的执行方式是先评估if，然后转到下一行以执行其余代码。使用cond时，如果表达式的计算结果为true，则它将返回该值，而不会计算其他表达式。

引用：https://clojuredocs.org/clojure.core/cond

使用Clojure语法重写Java if语句

2 个答案: