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#ifdef LOCAL
#include <bits/stdc++.h>
using namespace std;
// tree node stuff here...
#endif
/*
[[0,0,1,0,0],[0,0,0,0,0],[0,0,0,1,0],[1,1,0,1,1],[0,0,0,0,0]]
[0,4]
[4,4]
[[0,0,1,0,0],[0,0,0,0,0],[0,0,0,1,0],[1,1,0,1,1],[0,0,0,0,0]]
[0,4]
[3,2]
[[0,0,0,0,1,0,0],[0,0,1,0,0,0,0],[0,0,0,0,0,0,0],[0,0,0,0,0,0,1],[0,1,0,0,0,0,0],[0,0,0,1,0,0,0],[0,0,0,0,0,0,0],[0,0,1,0,0,0,1],[0,0,0,0,1,0,0]]
[0,0]
[8,6]
*/
static int __initialSetup = []()
{
std::ios::sync_with_stdio(false);
cin.tie(NULL);
return 0;
}
();
// handle special cases first
// [], "", ...
// range of input?
struct Data {
int x, y;
bool operator<(const Data &b) const
{
if (x == b.x) {
return y < b.y;
}
return x < b.x;
}
bool operator!=(const Data &b) const
{
return !(x == b.x && y == b.y);
}
};
class Solution
{
private:
int n, m;
const int dx[4] = {0, 0, 1, -1};
const int dy[4] = {1, -1, 0, 0};
bool in(Data &data)
{
return (0 <= data.x && data.x < n) && (0 <= data.y && data.y < m);
}
public:
bool hasPath(vector<vector<int>> &maze, vector<int> &start,
vector<int> &destination)
{
// Use BFS
// DFS will will have worse case that's really bad
n = maze.size();
if (n == 0)
return false;
m = maze[0].size();
if (m == 0)
return false;
queue<Data> q;
set<Data> seen;
Data nxt = Data{start[0], start[1]};
q.push(nxt);
seen.insert(nxt);
while (q.size() > 0) {
Data &cur = q.front();
q.pop();
if (cur.x == destination[0] && cur.y == destination[1])
return true;
for (int i = 0; i < 4; i++) {
nxt = Data{cur.x, cur.y};
while (in(nxt) && maze[nxt.x][nxt.y] == 0) {
nxt.x += dx[i];
nxt.y += dy[i];
}
nxt.x -= dx[i];
nxt.y -= dy[i];
if (in(nxt) && nxt != cur && maze[nxt.x][nxt.y] == 0) {
if (seen.count(nxt) == 0) {
q.push(nxt);
seen.insert(nxt);
}
}
}
}
return false;
}
};
#ifdef LOCAL
int main()
{
return 0;
}
#endif
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