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@fortil
Last active Oct 3, 2018
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S-Expression to binary tree in JavaScript
function SExpression(nodes) {
if (!/(\(|\))+/g.test(nodes)) {
return 'E5'
}
let a = nodes.split(' ').map(i => i.replace(/\(|\)/g, '').split(','))
let keyPair = a.map(i => i[0])
let valuePair = a.map(i => i[1])
let aE1 = keyPair.reduce((prev, curr) => {
prev[curr] = (prev[curr] || 0) + 1
return prev
}, {})
const E1 = Object.values(a).filter(e => e > 2)
if (E1.length) {
return 'E1'
}
let aE2 = (Array.from(new Set(a.map(e => JSON.stringify(e))))).map(e => JSON.parse(e))
if (aE2.length < a.length) {
return 'E2'
}
let aE4 = keyPair.filter(key => !valuePair.includes(key))
if (aE4.length > 2) {
return 'E4'
}
let aE3 = Array.from(new Set(valuePair))
if (aE3.length < valuePair.length) {
return 'E3'
}
let root = aE4[0]
let routes = getObj(a, root)
return getNodes(routes, root)
}
function getNodes(obj, key) {
return `(${key}${Object.keys(obj).reduce((prev, curr) => {
if (Object.keys(obj[curr]).length) {
prev += getNodes(obj[curr], curr)
} else {
prev += `(${curr})`
}
return prev
}, ``)})`
}
function getObj(a, key) {
return a.reduce((prev, curr) => {
if (curr[0] === key) {
prev[curr[1]] = getObj(a, curr[1])
}
return prev
}, {})
}
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