NOTE: The code snippet given may be incomplete or have compile time, runtime or logical errors.

How to attempt Debugging Exercise?

1. Copy the code to your code editor (e.g. VS Code).

2. Add relevant header files like “#include <iostream>” etc.

3. Run the code.

4. You will notice the expected output is not printing at the console.

5. Apply your smart coder mind to Debug the code.

6. Warning: Only see the solution after you have tried enough.

7. Debug the code. This is the merge array function of merge sort.

void merge(int arr[], int start, int mid, int end) {
    int left[mid - start + 1];
    int right[end - mid];
    for (int i = 0; i < mid - start; i++) {
        left[i] = arr[start + i];
    }
    for (int j = 0; j <= end - mid; j++) {
        right[j] = arr[mid + 1 + j];
    }
    int i = 0, j = 0, k = start;
    while (i < mid - start || j < end - mid) {
        if (left[i] <= right[j]) {
            arr[k] = left[i];
            i++;
        } else {
            arr[k] = right[j];
            j++;
        }
        k++;
    }
    while (i < mid - start) {
        arr[k] = left[i];
        i++;
        k++;
    }
    while (j <= end - mid) {
        arr[k] = right[j];
        j++;
        k++;
    }
}

1. Debug the code.

void merge_sort(int arr[], int start, int end) {
    int mid = (start + end) / 2;
    merge_sort(arr, start, mid-1);
    merge_sort(arr, mid+1, end);
    merge(arr, start, mid, end);
}

1. Debug the code.

int ceilSearch(int arr[], int low, int high, int x) {
	int mid;
	if (x < arr[low])
		return low;
	if (x >= arr[high])
		return -1;
	mid = (low + high) / 2;
	if (arr[mid] == x)
		return mid;
	else if (arr[mid] < x) {
		if (mid + 1 < high && x < arr[mid + 1])
			return mid + 1;
		else
			return ceilSearch(arr, mid + 1, high, x);
	}
	else {
		if (mid - 1 > low && x >= arr[mid - 1])
			return mid;
		else
			return ceilSearch(arr, low, mid - 1, x);
	}
}

1. Debug the code.

void print(int** board, int n){
    for(int i=0; i<n; i++){
        for(int j=0; j<n; j++){
            cout << board[i][j] << " ";
        }
    }
    cout << endl;
}

bool check_position(int** board, int col, int row){
    for(int j=0; j<n; j++){
        if(board[row][j]) return false;
    }
    for(int i=0; i<n; i++){
        if(board[i][col]) return false;
    }
    for(int i=0; i<n; i++){
        if((row+col-i)>=n || (row+col-i<0)) continue;
        if(board[i][row+col-i]) return false;
    }
    for(int i=0; i<n; i++){
        if((i-row+col)>=n || (i-row+col<0)) continue;
        if(board[i][i-row+col]) return false;
    }
    return true;
}

bool backtracing(int** board, int n, int row){
    if(row > n){
        print(board,n);
        return true;
    }
    for(int j=0; j<n; j++){
        if(check_position(board,j,row,n)){
            board[row][j] = 1;
            backtracing(board, n, row+1);
            board[row][j] = 0;
        }
    }
}

void placeNQueens(int n){
    int** board = new int*[n];
    for(int i=0; i<n; i++){
        board[i] = new int[n];
        for(int j=0; j<n; j++){
            board[i][j] = 0;
        }
    }
    backtracing(board, n, 0);
}

1. Debug the code.

void print(bool** visited, int n){
    for(int i=0; i<n; i++){
        for(int j=0; j<n; j++){
            cout << visited[i][j] << " ";
        }
    }
    cout << endl;
}

void solve(int maze[][, bool** visited, int row, int col, int n){
    if(row>n || col>n || row < 0 || col < 0) return; 
    if(!(!visited[row][col] && maze[row][col])) return;
    visited[row][col] = true;
    if(row==n-1 && col == n-1){
        print(visited, n);
    }
    solve(maze,visited,row,col+1,n);
    solve(maze,visited,row,col-1,n);
    solve(maze,visited,row+1,col,n);
    solve(maze,visited,row-1,col,n);
    visited[row][col] = false;
}

void ratInAMaze(int maze[][], int n){
	bool** visited = new bool*[n];
    for(int i=0; i<n; i++){
        visited[i] = new bool[n];
        for(int j=0; j<n; j++){
            visited[i][j] = false;
        }
    }
    solve(maze, visited, 0, 0, n);
}

1. Debug the code. Power(x^n)

int power(int x, int n){
    if(n == 0) return 1;
    if(x == 0) return 0;
    int temp = power(x, n/2);
    if(n % 2){
        return temp*temp;
    } else{
        return temp*temp*x;
    }
}

solution-1.txt

solution-2.txt

solution-3.txt

solution-4.txt

solution-5.txt

solution-6.txt