September 2017 Update

This commit is contained in:
Ingy döt Net 2017-09-23 10:01:46 +02:00
parent bba7bfd280
commit ba8067c3b7
14570 changed files with 153136 additions and 63871 deletions

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var arr = [
[55],
[94, 48],
[95, 30, 96],
[77, 71, 26, 67],
[97, 13, 76, 38, 45],
[07, 36, 79, 16, 37, 68],
[48, 07, 09, 18, 70, 26, 06],
[18, 72, 79, 46, 59, 79, 29, 90],
[20, 76, 87, 11, 32, 07, 07, 49, 18],
[27, 83, 58, 35, 71, 11, 25, 57, 29, 85],
[14, 64, 36, 96, 27, 11, 58, 56, 92, 18, 55],
[02, 90, 03, 60, 48, 49, 41, 46, 33, 36, 47, 23],
[92, 50, 48, 02, 36, 59, 42, 79, 72, 20, 82, 77, 42],
[56, 78, 38, 80, 39, 75, 02, 71, 66, 66, 01, 03, 55, 72],
[44, 25, 67, 84, 71, 67, 11, 61, 40, 57, 58, 89, 40, 56, 36],
[85, 32, 25, 85, 57, 48, 84, 35, 47, 62, 17, 01, 01, 99, 89, 52],
[06, 71, 28, 75, 94, 48, 37, 10, 23, 51, 06, 48, 53, 18, 74, 98, 15],
[27, 02, 92, 23, 08, 71, 76, 84, 15, 52, 92, 63, 81, 10, 44, 10, 69, 93]
];
while (arr.length !== 1) {
var len = arr.length;
var row = [];
var current = arr[len-2];
var currentLen = current.length - 1;
var end = arr[len-1];
for ( var i = 0; i <= currentLen; i++ ) {
row.push(Math.max(current[i] + end[i] || 0, current[i] + end[i+1] || 0) )
}
arr.pop();
arr.pop();
arr.push(row);
}
console.log(arr);

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[ [ 1320 ] ]

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(function () {
// Right fold using final element as initial accumulator
// (a -> a -> a) -> t a -> a
function foldr1(f, lst) {
return lst.length > 1 ? (
f(lst[0], foldr1(f, lst.slice(1)))
) : lst[0];
}
// function of arity 3 mapped over nth items of each of 3 lists
// (a -> b -> c -> d) -> [a] -> [b] -> [c] -> [d]
function zipWith3(f, xs, ys, zs) {
return zs.length ? [f(xs[0], ys[0], zs[0])].concat(
zipWith3(f, xs.slice(1), ys.slice(1), zs.slice(1))) : [];
}
// Evaluating from bottom up (right fold)
// and with recursion left to right (head and first item of tail at each stage)
return foldr1(
function (xs, ys) {
return zipWith3(
function (x, y, z) {
return x + (y < z ? z : y);
},
xs, ys, ys.slice(1) // item above, and larger of two below
);
}, [
[55],
[94, 48],
[95, 30, 96],
[77, 71, 26, 67],
[97, 13, 76, 38, 45],
[07, 36, 79, 16, 37, 68],
[48, 07, 09, 18, 70, 26, 06],
[18, 72, 79, 46, 59, 79, 29, 90],
[20, 76, 87, 11, 32, 07, 07, 49, 18],
[27, 83, 58, 35, 71, 11, 25, 57, 29, 85],
[14, 64, 36, 96, 27, 11, 58, 56, 92, 18, 55],
[02, 90, 03, 60, 48, 49, 41, 46, 33, 36, 47, 23],
[92, 50, 48, 02, 36, 59, 42, 79, 72, 20, 82, 77, 42],
[56, 78, 38, 80, 39, 75, 02, 71, 66, 66, 01, 03, 55, 72],
[44, 25, 67, 84, 71, 67, 11, 61, 40, 57, 58, 89, 40, 56, 36],
[85, 32, 25, 85, 57, 48, 84, 35, 47, 62, 17, 01, 01, 99, 89, 52],
[06, 71, 28, 75, 94, 48, 37, 10, 23, 51, 06, 48, 53, 18, 74, 98, 15],
[27, 02, 92, 23, 08, 71, 76, 84, 15, 52, 92, 63, 81, 10, 44, 10, 69, 93]
]
)[0];
})();

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function maximumTrianglePathSum(triangle) {
function distilLastLine() {
let lastLine = triangle.pop(),
aboveLine = triangle.pop();
for (let i = 0; i < aboveLine.length; i++)
aboveLine[i] = Math.max(
aboveLine[i] + lastLine[i],
aboveLine[i] + lastLine[i + 1]
);
triangle.push(aboveLine);
}
do {
distilLastLine();
} while (triangle.length > 1);
return triangle[0][0];
}
// testing
let theTriangle = [
[55],
[94, 48],
[95, 30, 96],
[77, 71, 26, 67],
[97, 13, 76, 38, 45],
[ 7, 36, 79, 16, 37, 68],
[48, 7, 9, 18, 70, 26, 6],
[18, 72, 79, 46, 59, 79, 29, 90],
[20, 76, 87, 11, 32, 7, 7, 49, 18],
[27, 83, 58, 35, 71, 11, 25, 57, 29, 85],
[14, 64, 36, 96, 27, 11, 58, 56, 92, 18, 55],
[ 2, 90, 3, 60, 48, 49, 41, 46, 33, 36, 47, 23],
[92, 50, 48, 2, 36, 59, 42, 79, 72, 20, 82, 77, 42],
[56, 78, 38, 80, 39, 75, 2, 71, 66, 66, 1, 3, 55, 72],
[44, 25, 67, 84, 71, 67, 11, 61, 40, 57, 58, 89, 40, 56, 36],
[85, 32, 25, 85, 57, 48, 84, 35, 47, 62, 17, 1, 1, 99, 89, 52],
[ 6, 71, 28, 75, 94, 48, 37, 10, 23, 51, 6, 48, 53, 18, 74, 98, 15],
[27, 2, 92, 23, 8, 71, 76, 84, 15, 52, 92, 63, 81, 10, 44, 10, 69, 93]
];
console.log(maximumTrianglePathSum(theTriangle));

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(() => {
'use strict';
// MAX PATH SUM -----------------------------------------------------------
// Working from the bottom of the triangle upwards,
// summing each number with the larger of the two below
// until the maximum emerges at the top.
// maxPathSum ::[[Int]] -> Int
const maxPathSum = xss =>
// A list of lists folded down to a list of just one remaining integer.
// The head function returns that integer from the list.
head(
foldr1(
// The accumulator, zipped with the tail of the
// accumulator, yields pairs of adjacent sums so far.
(ys, xs) => zipWith3(
// Plus greater of two below
(a, b, c) => a + max(b, c),
xs, ys, tail(ys)
),
xss
)
);
// GENERIC FUNCTIONS ------------------------------------------------------
// Right fold using final element as initial accumulator
// foldr1 :: (a -> a -> a) -> [a] -> a
const foldr1 = (f, xs) =>
xs.length > 0 ? init(xs)
.reduceRight(f, last(xs)) : [];
// head :: [a] -> a
const head = xs => xs.length ? xs[0] : undefined;
// init :: [a] -> [a]
const init = xs => xs.length ? xs.slice(0, -1) : undefined;
// last :: [a] -> a
const last = xs => xs.length ? xs.slice(-1)[0] : undefined;
// max :: Ord a => a -> a -> a
const max = (a, b) => b > a ? b : a;
// minimum :: [a] -> a
const minimum = xs =>
xs.reduce((a, x) => (x < a || a === undefined ? x : a), undefined);
// tail :: [a] -> [a]
const tail = xs => xs.length ? xs.slice(1) : undefined;
// Function of arity 3 mapped over nth items of each of 3 lists
// zipWith3 :: (a -> b -> c -> d) -> [a] -> [b] -> [c] -> [d]
const zipWith3 = (f, xs, ys, zs) =>
Array.from({
length: minimum([xs.length, ys.length, zs.length])
}, (_, i) => f(xs[i], ys[i], zs[i]));
// TEST -------------------------------------------------------------------
return maxPathSum([
[55],
[94, 48],
[95, 30, 96],
[77, 71, 26, 67],
[97, 13, 76, 38, 45],
[7, 36, 79, 16, 37, 68],
[48, 7, 9, 18, 70, 26, 6],
[18, 72, 79, 46, 59, 79, 29, 90],
[20, 76, 87, 11, 32, 7, 7, 49, 18],
[27, 83, 58, 35, 71, 11, 25, 57, 29, 85],
[14, 64, 36, 96, 27, 11, 58, 56, 92, 18, 55],
[2, 90, 3, 60, 48, 49, 41, 46, 33, 36, 47, 23],
[92, 50, 48, 2, 36, 59, 42, 79, 72, 20, 82, 77, 42],
[56, 78, 38, 80, 39, 75, 2, 71, 66, 66, 1, 3, 55, 72],
[44, 25, 67, 84, 71, 67, 11, 61, 40, 57, 58, 89, 40, 56, 36],
[85, 32, 25, 85, 57, 48, 84, 35, 47, 62, 17, 1, 1, 99, 89, 52],
[6, 71, 28, 75, 94, 48, 37, 10, 23, 51, 6, 48, 53, 18, 74, 98, 15],
[27, 2, 92, 23, 8, 71, 76, 84, 15, 52, 92, 63, 81, 10, 44, 10, 69, 93]
]);
})();