本文实例为大家分享了js实现指定红包顺序和金额的具体代码，供大家参考，具体内容如下
前言
朋友拜托而写
单个包最小金额为 0.01
如果除指定金额外，其余都为 0.01 ，最后尾包存在为0的几率
本算法通过了 1000000 次测试，出错率为百万分之3
效果展示
空包问题
红包算法
/*
param: float, int, int, float
param1:红包金额总额
param2:红包数目
param3:指定特殊红包
param4:指定特殊红包金额
*/
let getPrize = function (total, number, index, volume){
let allowance = total - volume;
let arr = [];
let i = 0;
while (i < number - 2){
// 指定[0.01,allowance-(i*0.01))
let temp = (Math.random()*(allowance - (number - 1 - i) * 0.01) + 0.01).toFixed(2);
// if(temp < 0) console.log(`temp:${temp}`);
temp = temp <= 0 ? 0.01 : temp;
arr.push(parseFloat(temp));
allowance = parseFloat((allowance - temp).toFixed(2));
i++;
// console.log(`arr:${arr}, i:${i}`);
// 如果出现小于0的分配情况，剥削强者均分
if (allowance <= 0){
// console.log(`alowance:${allowance}`);
let w = arr.filter((val,index)=>{
// console.log(`val:${val}`);
if (val > 0.01){
arr[index] = parseFloat((arr[index] - 0.01).toFixed(2));
return val;
}
});
if (w.length == 0){
allowance = 0;
} else {
allowance = 0.01;
}
}
}
// 最后一个放入
arr.push(parseFloat(allowance.toFixed(2)));
let result = arr;
return result.slice(0, index).concat(parseFloat(volume), result.slice(index));
}
测试样例
// Test sample
for (let m = 0; m < 10000; m++){
let total = (Math.random()*100 + 0.01).toFixed(2);
let number = Math.floor(Math.random()*20 +2);
while (total / number < 0.01){
number = Math.floor(Math.random()*20 +2);
}
let index = Math.floor(Math.random()*(number - 1));
let volume = (Math.random()*(total - 0.01*(number-1))+0.01).toFixed(2);
while (volume >= total || volume + 0.01*(number-1) > total){
// console.log(`xx:${volume}`);
volume = (Math.random()*(total - 0.01*(number-1))+0.01).toFixed(2);
volume = volume <= 0 ? 0.01 : volume;
}
let test = getPrize(total, number, index, volume);
// console.log(test);
let sum = test.reduce((total,val)=>total+=parseFloat(val));
sum = sum.toFixed(2);
if (sum !== total) {
console.log(`volume:${volume}, total: ${total}, number: ${number}`);
console.log(`sum:${sum}`);
console.log(test);
}
test.map((val,index)=>{
if (val <= 0 && index !== test.length - 1){
console.log(`volume:${volume}, total: ${total}, number: ${number}`);
console.log(`sum:${sum}`);
console.log(test);
}
});
}
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：https://blog.csdn.net/u013362192/article/details/115315607
dy("nrwz");