数据结构

两个数组的交集 II

function intersect(nums1: number[], nums2: number[]): number[] {
let arr1=new Array();
let arr2=new Array();
let result=new Array();
for(let i=0;i<nums1.length;i++){
    if(arr1[nums1[i]]===undefined)
        arr1[nums1[i]]=1
    else
        arr1[nums1[i]]=arr1[nums1[i]]+1
}
console.log(arr1)
for(let i=0;i<nums2.length;i++){
    if(arr2[nums2[i]]===undefined)
        arr2[nums2[i]]=1
    else
     arr2[nums2[i]]=arr2[nums2[i]]+1
}
console.log(arr2)
for(let i=0;i<Math.min(arr1.length,arr2.length);i++){
 if(arr1[i]!==undefined&&arr2[i]!==undefined){
     for(let j=0;j<Math.min(arr1[i],arr2[i]);j++){
         result.push(i)
     }
 }
}
return result
};

function intersect(nums1: number[], nums2: number[]): number[] {
let arr1=new Array();
let result=new Array();
for(let i=0;i<nums1.length;i++){
    if(arr1[nums1[i]]===undefined)
        arr1[nums1[i]]=1
    else
        arr1[nums1[i]]=arr1[nums1[i]]+1
}
for(let i=0;i<nums2.length;i++){
   if(arr1[nums2[i]]!==undefined&&arr1[nums2[i]]!==0){
       result.push(nums2[i])
       arr1[nums2[i]]--;
   }
}
return result
};

合并两个有序数组

function merge(nums1: number[], m: number, nums2: number[], n: number): void {
nums1.splice(m, n, ...nums2)
nums1.sort((a, b) => a - b);
};

重塑矩阵

/**
* @param {number[][]} mat
* @param {number} r
* @param {number} c
* @return {number[][]}
*/
var matrixReshape = function(mat, r, c) {
  const sums=mat.length*mat[0].length
  const n=mat[0].length
  let arr=new Array()
  let results=new Array()
  if(r*c!==sums){
    return mat
  }
  else{
    for (let i = 0; i < sums; i++) {
      arr.push(mat[parseInt(i/n)][i%n])
      if((i+1) % c==0){
        results.push(arr)
        arr=[]
      }
    }
    return results
  }
};

杨辉三角

有效的数独

var isValidSudoku = function(board) {
    const rows = new Array(9).fill(0).map(() => new Array(9).fill(0));
    const columns = new Array(9).fill(0).map(() => new Array(9).fill(0));
    const subboxes = new Array(3).fill(0).map(() => new Array(3).fill(0).map(() => new Array(9).fill(0)));
    for (let i = 0; i < 9; i++) {
        for (let j = 0; j < 9; j++) {
            const c = board[i][j];
            if (c !== '.') {
                const index = c.charCodeAt() - '0'.charCodeAt() - 1;
                rows[i][index]++;
                columns[j][index]++;
                subboxes[Math.floor(i / 3)][Math.floor(j / 3)][index]++;
                if (rows[i][index] > 1 || columns[j][index] > 1 || subboxes[Math.floor(i / 3)][Math.floor(j / 3)][index] > 1) {
                    return false;
                }
            }
        }
    }
    return true;
};

31. 下一个排列

删除有序数组中的重复项 II

/**
 * @param {number[]} nums
 * @return {number}
 */
var removeDuplicates = function(nums) {
    const n = nums.length;
    if (n <= 2) {
        return n;
    }
    let slow = 0, fast = 2;
    while (fast < n) {
        if (nums[slow] != nums[fast]) {
            nums[slow+2]=nums[fast]
            ++slow
        }
        ++fast

    }
    return slow+2;
};

螺旋矩阵

/**
 * @param {number[][]} matrix
 * @return {number[]}
 */
var spiralOrder = function (matrix) {
    let m = matrix.length;
    if (m === 0) return [];
    let res = [];
    let top = 0,
        bottom = m - 1,
        left = 0,
        right = matrix[0].length - 1;
    while (left < right && bottom > top) {
        for (let i = left; i < right; i++) res.push(matrix[top][i]);
        for (let i = top; i < bottom; i++) res.push(matrix[i][right]);
        for (let i = right; i > left; i--) res.push(matrix[bottom][i]);
        for (let i = bottom; i > top; i--) res.push(matrix[i][left]);
        top++;
        bottom--;
        left++;
        right--;
    }
    if (left === right) {
        for (i = top; i <= bottom; i++) res.push(matrix[i][left]);
    } else if (top === bottom) {
        for (i = left; i <= right; i++) res.push(matrix[top][i]);
    }
    return res;
};