61.机器人的运动范围

机器人的运动范围

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题目描述

地上有一个m行和n列的方格。一个机器人从坐标0,0的格子开始移动，每一次只能向左，右，上，下四个方向移动一格，但是不能进入行坐标和列坐标的数位之和大于k的格子。 例如，当k为18时，机器人能够进入方格（35,37），因为3+5+3+7 = 18。但是，它不能进入方格（35,38），因为3+5+3+8 = 19。请问该机器人能够达到多少个格子？

// 机器人的运动范围.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <string>
using namespace::std;

class Solution {
public:
	int movingCount(int threshold, int rows, int cols) {
		if (threshold < 0 || rows < 0 || cols < 0) return 0 ;

		bool* visited = new bool[rows * cols] ;
		memset(visited, 0, rows * cols) ;

		int count = 0 ;

		count = movingCountCore(threshold, rows, cols, 0, 0, visited) ;

		return count ;
	}

	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) == true) {
			visited[row * cols + col] = true ;
			count = 1 + movingCountCore(threshold, rows, cols, row + 1, col, visited)
				+ movingCountCore(threshold, rows, cols, row - 1, col, visited)
				+ movingCountCore(threshold, rows, cols, row, col + 1, visited)
				+ movingCountCore(threshold, rows, cols, row, col - 1, visited) ;
		}

		return count ;
	}

	bool check(int threshold, int rows, int cols, int row, int col, bool* visited) {
		if (row >= 0 && row < rows && col >= 0 && col < cols && digitalSum(row) + digitalSum(col) <= threshold && visited[row * cols + col] == false)
			return true ;
		else
			return false ;
	}

	int digitalSum(int num) {
		int sum = 0 ;
		while (num > 0) {
			int tmp = num % 10 ;
			sum += tmp ;
			num /= 10 ;
		}
		return sum ;
	}
};
int _tmain(int argc, _TCHAR* argv[])
{
	Solution s;
	int result = s.movingCount(5, 10, 10);
	return 0;
}

第三次做：

class Solution {
public:
    int movingCount(int threshold, int rows, int cols) {
        if ( threshold < 0 || rows < 0 || cols < 0 ) return 0 ;
        
        bool* visited = new bool[ rows * cols ] ;
        memset( visited, 0, rows * cols ) ;
        
        int count = 0 ;
        
		count = movingCountCore(threshold, rows, cols, 0, 0, visited) ;  

       	delete[] visited ;
        return count ;
    }
    
    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) == true) {  
            visited[row * cols + col] = true ;  
            count = 1 + movingCountCore(threshold, rows, cols, row + 1, col, visited)  
                + movingCountCore(threshold, rows, cols, row - 1, col, visited)  
                + movingCountCore(threshold, rows, cols, row, col + 1, visited)  
                + movingCountCore(threshold, rows, cols, row, col - 1, visited) ;  
        }  
  
        return count ;  
    }  
    
    bool check( int threshold, int rows, int cols, int row, int col, bool* visited ) {
        if ( row >= 0 && col >= 0 && row < rows && col < cols &&
             digitalSum( row ) + digitalSum( col ) <= threshold && 
             visited[row * cols + col] == false ) 
        {
            return true ;
        } else {
            return false ;
        }
    }
    
    int digitalSum( int num ) {
        int sum = 0 ;
        while ( num > 0 ) {
            sum += num % 10 ;
            num /= 10 ;
        }
        return sum ;
    }
};