《劍指offer》67.機器人的運動範圍

題目：地上有個m行n列的方格。一個機器人從座標(0,0)的格子開始移動，它每一次可以向左、右、上、下移動一格，但不能進入行座標和列座標的數位之和大於k的格子。
例如，當k爲18時，機器人能夠進入方格(35,37)，因爲3+5+3+7=18.但它不能進入方格(35,38)，因爲3+5+3+8=19.請問該機器人能夠達到多少格子？

思路：

實現代碼：

#include <iostream>

void searchallboard(int row, int col, int* cover, int* accept, int* pcount);
int sumofunits(int row, int col);

static int m;
static int n;
static int k;

int main()
{
    using namespace std;
    int count = 0;
    int* pcount = &count;
    int* cover;
    int* accept;

    cin >> m >> n >> k;

    cover = new int[m*n*sizeof(int)];
    accept = new int[m*n*sizeof(int)];
    memset(cover, 0, m*n*sizeof(int));
    memset(accept, 0, m*n*sizeof(int));

    for (int i = 0; i < m;i++)
    for (int j = 0; j < n; j++){
        cout << cover[n*i + j] << endl;
        cout << accept[n*i + j] << endl;
    }
    searchallboard(0, 0, cover, accept, pcount);
    cout << count;
    return 0;
}
void searchallboard(int row, int col, int* cover, int* accept, int* pcount)
{
    if (row<0 || row> m - 1 || col<0 || col> n - 1)
        return;
    if (*cover)
        return;

    if (sumofunits(row, col) <= k){
        *(cover) = 1;
        *(accept) = 1;
        (*pcount)++;
    }
    else{
        *(cover) = 1;
        *(accept) = 0;
    }

    searchallboard(row - 1, col, cover - n, accept - n, pcount);
    searchallboard(row + 1, col, cover + n, accept + n, pcount);
    searchallboard(row, col-1, cover - 1, accept - 1, pcount);
    searchallboard(row, col+1, cover + 1, accept + 1, pcount);
}
int sumofunits(int row, int col)
{
    int sum = 0;
    while (row){
        sum += row % 10;
        row /= 10;
    }
    while (col){
        sum += col % 10;
        col /= 10;
    }
    return sum;
}

踩過得坑和改進點：

另外附上官方帶測試用例的代碼：

/* 
	 * Question Description:
	 * (Question 31 in <Coding Intervies>) A robot starts at cell (0, 0) of a grid with m rows and n columns. 
	 * It can move to the left, right, up, and down, and moves one cell for a step. It cannot enter cells where 
	 * the digit sum of the row index and column index are greater than a given k. 
	*/
	
	#include <stdio.h>
	
	int getDigitSum(int number)
	{
	    int sum = 0;
	    while(number > 0)
	    {
	        sum += number % 10;
	        number /= 10;
	    }
	    
	    return sum;
	}
	
	bool check(int threshold, int rows, int cols, int row, int col, bool* visited)
	{
	    if(row >=0 && row < rows && col >= 0 && col < cols
	        && getDigitSum(row) + getDigitSum(col) <= threshold
	        && !visited[row* cols + col])
	        return true;
	    
	    return false;
	}
	
	int movingCountCore(int threshold, int rows, int cols, int row, int col, bool* visited)
	{
	    int count = 0;
	    if(check(threshold, rows, cols, row, col, visited)) 
	    {
	        visited[row * cols + col] = true;
	    
	        count = 1 + movingCountCore(threshold, rows, cols, 
	                    row - 1, col, visited)
	                + movingCountCore(threshold, rows, cols, 
	                    row, col - 1, visited)
	                + movingCountCore(threshold, rows, cols, 
	                    row + 1, col, visited)
	                + movingCountCore(threshold, rows, cols, 
	                    row, col + 1, visited);
	    }
	    
	    return count;
	}
	
	int movingCount(int threshold, int rows, int cols)
	{
	    bool *visited = new bool[rows * cols];
	    for(int i = 0; i < rows * cols; ++i)
	        visited[i] = false;
	        
	    int count = movingCountCore(threshold, rows, cols, 
	                    0, 0, visited);
	    
	    delete[] visited;
	    
	    return count; 
	}
	
	// ================================ test code ================================
	void test(char* testName, int threshold, int rows, int cols, int expected)
	{
	    if(testName != NULL)
	        printf("%s begins: ", testName);
	    
	    if(movingCount(threshold, rows, cols) == expected)
	        printf("Passed.\n");
	    else
	        printf("FAILED.\n");
	}
	
	void test1()
	{
	    test("Test1", 5, 10, 10, 21);
	}
	
	void test2()
	{
	    test("Test2", 15, 20, 20, 359);
	}
	
	void test3() 
	{
	    test("Test3", 10, 1, 100, 29);
	}
	
	void test4() 
	{
	    test("Test4", 10, 1, 10, 10);
	}
	
	void test5()
	{
	    test("Test5", 15, 100, 1, 79);
	}
	
	void test6()
	{
	    test("Test6", 15, 10, 1, 10);
	}
	
	void test7()
	{
	    test("Test7", 15, 1, 1, 1);
	}
	
	void test8()
	{
	    test("Test8", -10, 10, 10, 0);
	}
	
	int main(int agrc, char* argv[])
	{
	    test1();
	    test2();
	    test3();
	    test4();
	    test5();
	    test6();
	    test7();
	    test8();
	}