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0980-unique-paths-iii.cpp
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0980-unique-paths-iii.cpp
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class Solution {
public:
int res = 0, start_i, start_j, box = 1;
bool isInvalid(vector<vector<int>>& grid, int i, int j){
return (i<0 || j<0 || i>=grid.size() || j>=grid[i].size());
}
void dfs(vector<vector<int>> grid, int i, int j, int ct=0){
if(isInvalid(grid, i, j) || grid[i][j]==-1)
return;
if(grid[i][j]==2){
if(ct==box)
res++;
return;
}
grid[i][j] = -1;
dfs(grid, i, j+1, ct+1);
dfs(grid, i, j-1, ct+1);
dfs(grid, i+1, j, ct+1);
dfs(grid, i-1, j, ct+1);
grid[i][j] = 0;
}
int uniquePathsIII(vector<vector<int>>& grid) {
for(int i=0; i<grid.size(); i++){
for(int j=0; j<grid[i].size(); j++){
if(grid[i][j]==1)
start_i = i, start_j = j;
else if(!grid[i][j]) box++;
}
}
dfs(grid, start_i, start_j);
return res;
}
};