面试题13：机器人的运动范围

本题考察的是回溯算法，可以使用DFS解决问题。

C++版本

#include <iostream>
#include <vector>
using namespace std;

int getDigitSum(int num){
    int sum = 0;
    while(num > 0){
        sum += num%10;
        num/=10;
    }
    return sum;
}

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

int dfsmovingCountCore(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 + dfsmovingCountCore(threshold, rows, cols, row, col-1, visited)
        + dfsmovingCountCore(threshold, rows, cols, row, col+1, visited)
        + dfsmovingCountCore(threshold, rows, cols, row-1, col, visited)
        + dfsmovingCountCore(threshold, rows, cols, row+1, col, visited);
    }
    return count;
}

int movingCount(int threshold, int rows, int cols){
    if(threshold < 0 || rows < 1 || cols < 1)
        return 0;
    bool visited[rows*cols];
    memset(visited, false, sizeof(visited));
    int count = dfsmovingCountCore(threshold, rows, cols, 0, 0, visited);
    return count;
}

int main(){
    int a[5] = {1,2,3,4,5};
    cout<<&a[2]<<" "<<&a[3]<<endl;
    cout<<Fibonacci(6)<<endl;
    return 0;
}