N*N矩阵，其中0是表示可以走的，1表示无法走，矩阵由二维数组表示，左上角是入口，右下角是出口，只能横着走和竖着走，要求找出最短路径。
#include<bits/stdc++.h>
using namespace std;
int mymax = 10000;
int f[4][2] = { {-1,0},{1,0},{0,-1},{0,1} };
int a[20][20], v[20][20], v1[20][20];
int l = 1;
int n;//矩阵规模
bool check(int x1, int y1)
{
if (x1 < 0 || x1 >= n ||_____(1)________) return false;
if (a[x1][y1] == 1 || _____(2)______ )return false;
return true;
}
void dfs(int x, int y)
{
if (x == n - 1 && y == n - 1)
{
if (l < mymax) {
mymax = l;
memcpy(v1, v, sizeof(v1));
}
return;
}
for (int k = 0; k < 4; k++) {
int x1,y1;
x1 = x + _____(3)_____;
y1 = y + _____(4)_____;
if (check(x1, y1)) {
_____(5)______;
_____(6)______;
dfs(x1, y1);
_____(7)______;
v[x1][y1] = 0;
}
}
}
int main()
{
cin >> n;
for (int i = 0; i < n; i++)
{
for (int j = 0; j < n; j++)
cin >> a[i][j];
}
dfs(0, 0);
int d = v1[n - 1][n - 1];
int x = n - 1, y = n - 1;
int k;
int qn[400][2];
qn[0][0] = n - 1;
qn[0][1] = n - 1;
for (k = 1;; k++)
{
x = x - f[d-1][0];
y = y - f[d-1][1];
qn[k][0] = x;
qn[k][1] = y;
d = v1[x][y];
if (x == 0 && y == 0) break;
}
for (int i = k; i >= 0; i--)
cout<<_____(8)_____<<","<<_____(9)_______<<endl;
return 0;
}
