TinyScript
commented
2 years ago Day - 02
完成算法：https://leetcode-cn.com/problems/shortest-distance-to-a-character/
第一版：
var shortestToChar = function(s, c) {
const len = s.length;
const result = new Array(len);
let mainCur = 0;
let subCur = 0;
let prevSign = 0;
let nextSign = 0;
while(mainCur < len) {
while(!nextSign && subCur < len) {
if(s[subCur] === c) {
if(mainCur === 0) prevSign = subCur
nextSign = subCur;
subCur++;
break;
}
subCur++;
}
const prev = Math.abs(prevSign - mainCur)
const next = Math.abs(nextSign - mainCur)
const currDistance = Math.min(prev, next);
if(!currDistance) {
prevSign = nextSign
nextSign = 0
}
result[mainCur] = currDistance
mainCur++
}
return result
};第二版：
var shortestToChar = function(s, c) {
const len = s.length;
const arr = [-Infinity];
const result = [];
for(let i = 0; i < len; i++) {
s.charAt(i) === c && arr.push(i);
}
arr.push(Infinity);
for(let i = 0; i < len; i++) {
if(s.charAt(i) === c) {
arr.shift();
result.push(0);
continue;
}
const resNum = Math.min(i - arr[0], arr[1] - i);
result.push(resNum);
}
return result;
};第三版：
思路
- 第一次遍历字符串，收集关键索引
- 第二次遍历字符串，根据关键索引计算距离
- 计算距离时，取关键索引最前2个值进行计算，取最小值
- 为了计算方便，关键索引数组的前后可加正负最大值
var shortestToChar = function(s, c) {
const len = s.length;
const result = [];
const keyArr = [-Infinity];
for(let i = 0; i < len; i++) {
if(s.charAt(i) === c) keyArr.push(i);
}
keyArr.push(Infinity);
let idx = 1, prev = keyArr[idx - 1], next = keyArr[idx];
for(let i = 0; i < len; i++) {
const dist = Math.min(i - prev, next - i);
result.push(dist);
if(i === next) {
idx++;
prev = next;
next = keyArr[idx];
}
}
return result;
};Symbol实现，参考：https://gist.github.com/liril-net/4436fb0bdc8f8ddecbdd34bdfa571b14 第一版：
function SymbolPolyfill(description) {
if(this instanceof SymbolPolyfill) throw new TypeError('Symbol is not a constructor');
if(description !== undefined) {
descString = String(description)
}
const symbol = Object.create(SymbolPolyfill.prototype)
Object.defineProperties(symbol, {
__Description__: { value: description },
__Name__: { value: generateName(description) },
})
return symbol
}
var generateName = (function() {
const createdMap = {}
return function (description) {
let suffix = createdMap[description]
if(!suffix) suffix = 0
suffix += 1
createdMap[description] = suffix
return `@@${description}${suffix}`
}
})()
var symbolA = SymbolPolyfill('a')
var symbolA1 = SymbolPolyfill('a')第二版：
思路：
- 禁止new，将desc转String
- 使用实例对象作为唯一值
-
给实例对象添加辨别属性，使用传入的desc入参填充
function SymbolPolyfill(desc) { if(this instanceof SymbolPolyfill) throw new Error('SymbolPolyfill is not a constructor.'); if (desc) { desc = String(desc); } const symbol = Object.create(SymbolPolyfill.prototype); Object.defineProperties(symbol, { __Name__: defineValue(getName(desc)), __Description__: defineValue(desc) }) return symbol; }
function defineValue(value) { return { value, configurable: true, enumable: false, writable: false } }
var getName = (() => {
const m = new Map();
return value => {
const count = m.get(value) || 0;
m.set(value, count + 1);
return @@${value}_${count + 1}
}
})()
就像上图那样，绿色
Day - 01
完成算法：https://leetcode-cn.com/problems/add-to-array-form-of-integer/submissions/
思路：
1. 数组的单位计算处理
2. k值的单位计算处理
3. 进位数处理
4. 最高位数进1处理
5. 如何保证num和k的值被加完
优化版：
思路：
以上3点做加法循环，直到k = 0且num遍历完
实现柯里化：
思路