生成n个随机数，要求n个数的和等于100

// 生成n个随机数，要求n个数的和等于100

function lessANumber(n, v) {

    var i,

        s = 0,

        r = [],

        x = v;

    for (i = 1; i < n; i++) {

        x = Math.random() * x;

        r.push(x.toFixed(0));

        s += x;

        x = v - s;

    }

    r.push(x.toFixed(0));

    return r;

}

function random(Min,Max){

         var Range = Max - Min;

         var Rand = Math.random();

         return(Min + Math.round(Rand * Range));

    }

    function randnum(n,max){

        var arr = [];

        if(max > 0){

            for(var i = 0;i<n;i++){

                var num = 0;

                    if(i == (n-1)){

                        num = max;

                    }else{

                        if(max <= 0){

                            num = max = 0;

                        }else{

                            num = random(0,max);

                            max -= num;

                        }

                    }

                arr.push(num);

            }

        }

        return arr;

    }

function foo($n ,$max = 100){

    $array = $zero = $normal = [];

    for($i=1;$i<=$n;$i++){

        $array[] = mt_rand(0,100);

    }

    $k = $max / array_sum($array);  //求出放大系数k

    foreach($array as $key => $val){

        $value = floor($val * $k); //直接保留整数，以保证下一步的和肯定<100

        if($value<1){

            $zero[] = $value;

        }else{

            $normal[] = $value;

        }

    }

    $sum = array_sum($normal);

    $diff = $max - $sum; //这个值肯定<100

    if(!empty($zero)){ //如果有为0的值

        $count = count($zero);

        foreach($zero as $z){

            $normal[] = $diff / $count;

        }

    }else{ //随机分配给一个人

        $key = array_rand($normal);

        $normal[$key] = $normal[$key]+$diff;

    }

    unset($array,$zero,$sum,$diff);

    return $normal;

}

javascript里的Math.random() 函数， 在php里

function random($min = 0, $max = 1)

{

    return $min + mt_rand()/mt_getrandmax()*($max-$min);

}