迴旋矩陣

var n = 11;

var arr = [];
for (var i=0; i<n; i++) {
    if (!arr[i]) {
        arr[i] = [];
    }
    for (var j=0; j<n; j++) {
        arr[i][j] = null;        
    }
}

var i=0,j=0,k=0,b=0;  
for (var i=0; i< n/2; i++) {
	console.log('------i : ' + i);
    for (var j=i; j<n-i; j++) {
    	arr[i][j] = ++b;
    }
    console.log('--------j :' + j);
    for (k = i+1,j--; k < n-i; k++) {
    	arr[k][j] = ++b;
    }
    console.log('--------k :' + k);
    for (j=--k,j--; j>=i; j--) {
    	arr[k][j] = ++b;
    }
    console.log('--------k :' + k);
    for (k--; k>i; k--) {
    	arr[k][i] = ++b;
    }
}

for (var i=0; i<arr.length; i++) {
 	var str = '';
 	for (var j=0; j<arr[i].length; j++) {
 		if (arr[i][j] < 10) {
			str += (arr[i][j] + '    ');
 		} else if (arr[i][j] < 100) {
			str += (arr[i][j] + '   ');
 		} else {
 			if (arr[i][j] == null) {
 				console.log('---------111 ');
 				str += ('   ');
 			} else 
 				str += (arr[i][j] + '  ');
 		}
 	}
 	str += '\n';
 	console.log(str);
 }