Spiral Matrix II
Desicription
Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order.
For example,
Given n = 3,
You should return the following matrix:
代码语言：javascript复制[
[ 1, 2, 3 ],
[ 8, 9, 4 ],
[ 7, 6, 5 ]
]Solution
代码语言：javascript复制class Solution {
private:
bool isValid(vector<vector<int> >& matrix, int x, int y, int n){
if(x < 0 || x >= n || y < 0 || y >= n || matrix[x][y] == INT_MIN)
return 0;
return 1;
}
public:
vector<vector<int>> generateMatrix(int n) {
vector<vector<int>> matrix(n, vector<int>(n, 0));
vector<vector<int>> res(n, vector<int>(n, 0));
int x = 0;
int y = 0;
int val = 1;
while(1){
bool flag = 0;
while(isValid(matrix, x, y, n))
res[x][y] = val , matrix[x][y] = INT_MIN, y , flag = 1;
y--;
x ;
while(isValid(matrix, x, y, n))
res[x][y] = val , matrix[x][y] = INT_MIN, x , flag = 1;
x--;
y--;
while(isValid(matrix, x, y, n))
res[x][y] = val , matrix[x][y] = INT_MIN, y--, flag = 1;
y ;
x--;
while(isValid(matrix, x, y, n))
res[x][y] = val , matrix[x][y] = INT_MIN, x--, flag = 1;
x ;
y ;
if(!flag)
return res;
}
}
};
