最长公共前缀#

// 横向比较
/**
 * @param {string[]} strs
 * @return {string}
 */
var longestCommonPrefix = function(strs) {
    if(strs.length === 0) return "";
    return strs.reduce( (pre, cur) => {
        var tmp = "";
        for(let i=0;i<pre.length; ++i){
            if(pre[i] === undefined || pre[i] !== cur[i]) break;
            else tmp += cur[i];
        }
        return tmp;
    })
};

// 纵向比较
/**
 * @param {string[]} strs
 * @return {string}
 */
var longestCommonPrefix = function(strs) {
    var n = strs.length;
    var target = "";
    var interrupt = false;
    var i = -1;
    while(true) {
        ++i;
        if(!strs[0]) return "";
        var tmp = strs[0][i];
        for(let k=0; k<n; ++k){
            if(strs[k][i] === undefined || tmp !== strs[k][i]) {
                interrupt = true;
                break;
            }
        }
        if(interrupt) break;
        target = `${target}${tmp}`;
    }
    return target;
};