LeetCode-165-比较版本号

/**
     * @param {string} version1
     * @param {string} version2
     * @return {number}
     */
var compareVersion = function(version1, version2) {
    //split分割字符串为数组
    let arr1 = version1.split('.')
    let arr2 = version2.split('.')
    //然后将对应下标的数值进行对比大小
    //有‘01’和‘001’ 转换成数值对比
    let max = Math.max(arr1.length, arr2.length)
    for(let i = 0; i < max; i++) {
        //如果不存在对应的数值
        // parseInt(undefined)是NAN 就默认取值为0
        let number1 = parseInt(arr1[i]) || 0
        let number2 = parseInt(arr2[i]) || 0
        console.log(number1, number2)
        if(number1 > number2) {
            return 1
        }else if(number2 > number1){
            return -1
        } 
    }
    return 0
};

/**
 * @param {string} version1
 * @param {string} version2
 * @return {number}
 */
var compareVersion = function(version1, version2) {
    //双指针
    //直接跳过.提取数值比大小
    let i = 0
    let j = 0
    //外层循环用于 逻辑上分割.之间的部分
    while(i < version1.length || j < version2.length) {
        let sum1 = 0
        let sum2 = 0
        //内层循环用于将点之间的数值提取出来 加和直接进行相互比大小
        while(i < version1.length && version1[i] !== '.') {
            sum1 = sum1 * 10 + parseInt(version1[i])
            //指针右移
            i++
        }
        while(j < version2.length && version2[j] !== '.') {
            sum2 = sum2 * 10 + parseInt(version2[j])
            j++
        }
        if(sum1 > sum2) {
            return 1
        }else if(sum1 < sum2) {
            return -1
        }
        //跳过点号
        i++
        j++
    }
    return 0
};