[LeetCode101]Spiral Matrix2

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:

[
 [ 1, 2, 3 ],
 [ 8, 9, 4 ],
 [ 7, 6, 5 ]
]

Analysis:

Similiar with the former one Spiral Matrix

Java

public int[][] generateMatrix(int n) {
        int [][] result = new int[n][n];
        int x1=0;
        int y1=0;
        int x2=n-1;
        int y2 = n-1;
        int val = 1;
        while(x1<=x2 && y1<=y2){
        	for(int i=y1;i<=y2;i++)
        		result[x1][i] = val++;
        	for(int j = x1+1;j<=x2;j++)
        		result[j][y2] = val++;
        	if(x1!=x2)
        		for(int i=y2-1;i>=y1;i--)
        			result[x2][i] = val++;
        	if(y1!=y2)
        		for(int j=x2-1;j>y1;j--)
        			result[j][y1]=val++;
        	x1++;y1++;x2--;y2--;
        }
        return result;
    }

c++

vector<vector<int> > generateMatrix(int n) {
        vector<vector<int>> matrix(n);
     if(n == 0) return matrix;
     for(int i=0; i<n; i++){
        matrix[i].resize(n);
     }
     int x1 = 0;
     int y1 = 0;
     int x2 = n - 1;
     int y2 = n - 1;
     int val = 1;
     while(x1<=x2 && y1<=y2){
        for(int j = y1; j<=y2; ++j)
            matrix[x1][j] = val++;
        for(int i = x1+1; i<=x2; ++i)
            matrix[i][y2] = val++;
        if(x2 !=x1)
            for(int j = y2-1; j>=y1; --j)
                matrix[x2][j] = val++;
        if(y2 != y1)
            for(int i = x2-1; i>x1; --i)
                matrix[i][y1] = val++;
        x1++, y1++, x2--, y2--;
     }
     return matrix;
    }