spend.js

const typeReturn = {
    498: 80,
    320: 60,
    245: 40
}

// var Combinatorics = require('js-combinatorics');
// Combinatorics.permutation([498, 320, 245]).toArray();
const allChoices = [
    [498, 320, 245],
    [498, 245, 320],
    [320, 498, 245],
    [320, 245, 498],
    [245, 320, 498],
    [245, 498, 320]
];

const state = {};
const steps = [498, 320, 245];

function getChoinceSpend(choices) {
    let totalSpend = 0;
    let rewardTotal = 0;
    choices.forEach(price => {
        let needSpend = 0;
        let r = typeReturn[price];
        if(rewardTotal > 0 ){
            needSpend = price - rewardTotal;
            rewardTotal = 0;
        } else{
            needSpend = price;
        }

        const num = Math.floor(needSpend / 100);
        const reward = num * r;
        totalSpend += needSpend;
        if(needSpend > 0) {
            rewardTotal += reward;
        }
        // console.log({
        //     num,
        //     reward,
        //     needSpend,
        //     rewardTotal
        // });
    })

    console.log({
        totalSpend,
        rewardTotal
    }, choices.join('-'))
}


// getChoinceSpend(allChoices[1])
allChoices.forEach(_ => {
    getChoinceSpend(_);
})