Max Profits

// Given an array of Stock Prices of the day

// Calculate the Maximum Profits that could be made from single BUY-SELL trade,

// given that you must first BUY and then SELL

var stockPrices = [10, 7, 5, 8, 11, 9];

function minPrice( arr ){

var result = [];

if(Array.isArray(arr)){

result = arr.reduce((prev,curr,i)=>{return (prev&&prev.length>0)?prev[1]>=curr?[i,curr]:prev:[i,curr]},[]) ;

}

return result;

}

function maxPrice(arr,minPrice){

minPrice = minPrice || [];

var result =[];

if( Array.isArray(arr)){

var startIndex = minPrice[0] || 0;

result = arr.slice(startIndex).reduce((prev,curr,i)=>{

if( prev&&prev.length>0){

if(prev[1]<curr){

return[startIndex+i,curr];

} else{

return prev;

}

} else {

return [startIndex+i,curr];

}

},[]);

}

return result;

}

console.log(minPrice(stockPrices));

console.log(maxPrice(stockPrices,minPrice(stockPrices)));

var minPrice = minPrice(stockPrices);

var maxPrice = maxPrice(stockPrices,minPrice);

console.log("Max Profit : ", maxPrice[1] - minPrice[1] );

console.log(`Buying at ${minPrice[0]} and selling at ${maxPrice[0]}`)