返回不是从if语句(递归)java中分离出来的

Question

我目前的作业是递归，这就是为什么我在这里没有使用for循环的原因。

基本上我想返回数组的最终行列式。 我可以得到我正在寻找的答案，但即使我在那里有一个返回语句，出于某种原因，程序会继续循环一次。

我的输出如下所示：

j1: 0
j1: 2
j3: 0
n3: 2
j4: 0
n4: 2
j5: 1
j5: 2
j1: 1
j1: 2
j3: 1
n3: 2
j4: 1
n4: 2
j5: 2
j5: 2
j1: 2
j1: 2
Final Det2: 3
j2: 2
n2: 2
j6: 2
n6: 2
j6: 1
n6: 2
Returned value: 18

这基本上意味着我的 j 值以某种方式从 2 变回 1？

public class Lab2 {

public static void main(String[] args) {
int[][] inputArray = new int[][]{{2, 3},{5,9}};
int[][] initialArray = new int[][]{{2, 3},{5,9}};
int j = 0;
int n = inputArray.length;
int finalDet = 0;
System.out.println("Returned value: " + determinant(inputArray, j, initialArray, finalDet, n));
}
//power function works!
public static int power(int i, int j){
int power = (int) Math.pow(-1, i+j);
return power;
}
public static int determinant(int[][] inputArray, int j, int[][]initialArray, int finalDet, int n){ 
inputArray = initialArray;
int minorLength = n;
int[][] detArray = new int[n-1][n-1];
int[][] detStep = new int[n][n];
int row = 1; //starts row for minor at 1 since top row is always deleted
int detColumn = 0; //index for columns start at 0
int inColumn = 0;
System.out.println("j1: "+j);
System.out.println("j1: "+n);  
if(j == n){
System.out.println("Final Det2: "+ finalDet);
System.out.println("j2: "+j);
System.out.println("n2: "+n);
return finalDet;
}
if(n == 1){
return finalDet;
}
System.out.println("j3: "+j);
System.out.println("n3: "+n);


//this part does the det function summation
if (j<n){
//this part gets the minor until it is small enough to work with
if (minorLength>1){ 
detArray = minor(inputArray, detArray, row, 0, 0, j, minorLength);
System.out.println("j4: "+j);
System.out.println("n4: "+n);
inputArray = detArray;
minorLength = inputArray[0].length;
}
finalDet = finalDet + power(0,j)*inputArray[0][0]*initialArray[0][j];
j++;
System.out.println("j5: "+j);
System.out.println("j5: "+n);
determinant(inputArray, j, initialArray, finalDet, n);
}
System.out.println("j6: "+j);
System.out.println("n6: "+n);
return finalDet;
}

//minor function works!!!
//this would be so much easier to do iteratively!!!
public static int[][] minor(int[][] inputArray, int[][] detArray, int row, int detColumn, int inColumn, int j, int n){ //start row at 1, not 0
if (row < n){
if(inColumn < n){
if (inColumn == j){
minor(inputArray, detArray, row, detColumn, inColumn+1, j, n);
}
if (inColumn != j){
detArray[row-1][detColumn] = inputArray[row][inColumn];
minor(inputArray, detArray, row, detColumn+1, inColumn+1, j, n);
}
}
if (inColumn == n){
minor(inputArray, detArray, row+1, 0, 0, j, n);
}
}
/*for (int dispRow = 0; dispRow < detArray.length; dispRow++){
for (int dispCol = 0; dispCol < detArray.length; dispCol++){
System.out.print(detArray[dispRow][dispCol]);
}
System.out.println("");
}   */
return detArray;
}
}

Answer 1

j == 1时您不会返回任何内容。我怀疑这就是问题所在。

Answer 2

显然问题是：

determinant(inputArray, j, initialArray, finalDet, n);

将其设置为等于返回变量停止额外的循环给了我正确的输出。 去想办法！

finalDet= determinant(inputArray, j, initialArray, finalDet, n);