动态规划算法-最长公共子序列的问题（附带函数缓存实现）

测试：
node subseq.js

subseq.js

const {cache,time} = require('./aop');
/**
 * 最长公共子序列的问题
 * http://www.cnblogs.com/huangxincheng/archive/2012/11/11/2764625.html
 * 
 */
function mcs(seqA,seqB){
    let lenA = seqA.length;
    let lenB = seqB.length;
    if(lenA==0 || lenB ==0){
        return '';
    }else{
        let tailA = seqA[lenA-1];
        let tailB = seqB[lenB-1];
        let subA = seqA.substr(0,lenA-1);
        let subB = seqB.substr(0,lenB-1);
        if(tailA===tailB){
            return mcs(subA,subB)+tailA;
        }else{
            let res1 = mcs(subA,seqB);
            let res2 = mcs(seqA,subB);
            return res1.length>res2.length?res1:res2;
        }
    }
}

mcs = cache(mcs);
cache.clear();
function main(){
    let seqA = '<artifactId>mybatisplus-spring-boot-starter</artifactId>';
    let seqB = '<artifactId>spring-boot-starter-jdbc</artifactId>';
    let res = mcs(seqA,seqB);
    console.info(`最长公共子序列：${res}`);
}
time(main)();
const costTime = time.costTime;
console.info(`耗时：${costTime}ms`);

aop.js

/**
 * 将函数变成具有缓存功能的函数
 * 
 * */
function cache(func){
    let mycache = cache.cache;
    if(mycache==null){
        mycache = cache.cache = {};
    }else{
        let curFuncName = cache.funcName;
        if(curFuncName!=func.name){
            cache.cache = {};
            cache.funcName = func.name;
        }
    }
    return function(...args){
        let key = JSON.stringify(args);
        if(mycache[key]!==undefined){
            //console.info(`get value form cache, mycache[${key}]=${mycache[key]}`);
            return mycache[key];
        }else{
            mycache[key] = func(...args);
            return mycache[key];
        }
    };
}
cache.clear = function(){
    cache.cache = {};
}

/**
 * 计时
 * */
const time = function(func){
    return function(...args){
        const begin = Date.now();
        const res = func(...args);
        const end = Date.now();
        time.costTime = end-begin;
        return res;
    };
};
module.exports = {cache,time};

最新代码地址https://github.com/zhoujiaping/doc/blob/master/nodenode/algol/aop.js