数组-螺旋矩阵

M螺旋矩阵 ||（leetcode59）

/*** @param {number} n* @return {number[][]}*/
var generateMatrix = function(n) {const maxNum = n * n;let curNum = 1;const matrix = new Array(n).fill(0).map(() => new Array(n).fill(0));let row = 0,column = 0;const directions = [[0, 1], [1, 0], [0, -1], [-1, 0]]; //右下左上let directionIndex = 0;while (curNum <= maxNum) {matrix[row][column] = curNum;curNum++;const nextRow = row + directions[directionIndex][0], nextColumn = column + directions[directionIndex][1];if (nextRow < 0 || nextRow >= n || nextColumn < 0 || nextColumn >= n || matrix[nextRow][nextColumn] !== 0) {directionIndex = (directionIndex + 1) % 4; //顺时针旋转至下一个方向}row = row + directions[directionIndex][0];column = column + directions[directionIndex][1];}return matrix;
};

M螺旋矩阵（leetcode54）

/*** @param {number[][]} matrix* @return {number[]}*/
var spiralOrder = function(matrix) {let left = 0; //四个边界let right = matrix[0].length - 1;let top = 0;let bottom = matrix.length - 1;let res = []; //存储结果while(true) {for(let i = left; i <= right; i++) {res.push(matrix[top][i]);}top++;if (top > bottom) break; // 四个边，每个边结束都判断是否终止for (let i = top; i <= bottom; i++) {res.push(matrix[i][right]);}right--;if (right < left) break;for (let i = right; i >= left; i--) {res.push(matrix[bottom][i]);}bottom--;if(bottom < top) break;for(let i = bottom; i >= top;i--) {res.push(matrix[i][left]);}left++;if(left > right) break;}return res;
};

E螺旋遍历二维数组（leetcode146）

/*** @param {number[][]} array* @return {number[]}*/
var spiralArray = function(array) {if (!array.length || !array[0].length) {return [];}const rows = array.length, columns = array[0].length;const visited = new Array(rows).fill(0).map(() => new Array(columns).fill(false));const total = rows * columns;const order = new Array(total).fill(0);let directionIndex = 0, row = 0, column = 0;const directions = [[0, 1], [1, 0], [0, -1], [-1, 0]];for (let i = 0; i < total; i++) {order[i] = array[row][column];visited[row][column] = true;const nextRow = row + directions[directionIndex][0], nextColumn = column + directions[directionIndex][1];if (!(0 <= nextRow && nextRow < rows && 0 <= nextColumn && nextColumn < columns && !(visited[nextRow][nextColumn]))) {directionIndex = (directionIndex + 1) % 4;}row += directions[directionIndex][0];column += directions[directionIndex][1];}return order;
};