数组 - 两个数组的交集 II

var setCache = function (cache, num) {
    if (!cache[num]) {
        cache[num] = 1;
    } else {
        cache[num] = cache[num] + 1;
    }
}

/**
 * @param {number[]} nums1
 * @param {number[]} nums2
 * @return {number[]}
 */
var intersect = function(nums1, nums2) {
    var cacheLong = {};
    var cacheShort = {};

    var numsLong = [];
    var numsShort = [];

    var result = [];

    if (nums1.length > nums2.length) {
        numsLong = nums1;
        numsShort = nums2;
    } else {
        numsLong = nums2;
        numsShort = nums1;
    }

    var i = 0;

    while(i < numsLong.length) {
        if (numsLong[i] !== undefined) {
            setCache(cacheLong, numsLong[i]); 
        }
        
        if (numsShort[i] !== undefined) {
            setCache(cacheShort, numsShort[i]); 
        }

        i++;
    }

    for (var k in cacheShort) {
        if (cacheLong[k] && cacheShort[k]) {
            var count = cacheLong[k] > cacheShort[k]
                ? cacheShort[k]
                : cacheLong[k];

            for (var i = 0 ; i < count ; i++) {
                result.push(k);
            }
        }
    }

    return result;
};

/**
 * @param {number[]} nums1
 * @param {number[]} nums2
 * @return {number[]}
 */
var intersect = function(nums1, nums2) {
  const map = {}
  if (nums1.length > nums2.length) [nums1, nums2] = [nums2, nums1]
  nums1.forEach(num => {
    if (!map[num]) map[num] = 1
    else map[num]++
  })
  return nums2.filter(num => {
    if (map[num] > 0) {
      map[num]--
      return true
    }
    return false
  })
};

var intersect = function (num1, num2) {
    const result = [];

    let n1i = 0;
    let n2i = 0;

    while (num1[n1i] !== undefined && num2[n2i] !== undefined) {
        let n1 = num1[n1i];
        let n2 = num2[n2i];

        if (n1 === n2) {
            result.push(n1);

            n1i++;
            n2i++;
        } else if (n1 > n2) {
            n2i++;
        } else {
            n1i++;
        }
    }

    return result;
}

var intersect = function (num1, num2) {
    const cache1 = {};
    const resule = [];
    let matchIndex = 0;

    num1.forEach(v => {
        if (cache1[v]) {
            cache1[v] += 1;
        } else {
            cache1[v] = 1;
        }
    });

    for (let i = 0 ; i < num2.length ; i++) {
        let n2 = num2[i];

        if (matchIndex >= num1.length) {
            break;
        } else {
            if (cache1[n2]) {
                resule.push(n2);

                cache1[n2]--;
                matchIndex++;
            }
        }
    }

    return result;
}