我认为以下几点可以达到你的目的
function func( orig, target ) {
var i = orig.length, j = 0, total = 0, change, newVals = [], next, factor1, factor2, len = orig.length, marginOfErrors = [];
// map original values to new array
while( i-- ) {
total += newVals[i] = Math.round( orig[i] );
}
change = total < target ? 1 : -1;
while( total !== target ) {
// Iterate through values and select the one that once changed will introduce
// the least margin of error in terms of itself. e.g. Incrementing 10 by 1
// would mean an error of 10% in relation to the value itself.
for( i = 0; i < len; i++ ) {
next = i === len - 1 ? 0 : i + 1;
factor2 = errorFactor( orig[next], newVals[next] + change );
factor1 = errorFactor( orig[i], newVals[i] + change );
if( factor1 > factor2 ) {
j = next;
}
}
newVals[j] += change;
total += change;
}
for( i = 0; i < len; i++ ) { marginOfErrors[i] = newVals[i] && Math.abs( orig[i] - newVals[i] ) / orig[i]; }
// Math.round() causes some problems as it is difficult to know at the beginning
// whether numbers should have been rounded up or down to reduce total margin of error.
// This section of code increments and decrements values by 1 to find the number
// combination with least margin of error.
for( i = 0; i < len; i++ ) {
for( j = 0; j < len; j++ ) {
if( j === i ) continue;
var roundUpFactor = errorFactor( orig[i], newVals[i] + 1) + errorFactor( orig[j], newVals[j] - 1 );
var roundDownFactor = errorFactor( orig[i], newVals[i] - 1) + errorFactor( orig[j], newVals[j] + 1 );
var sumMargin = marginOfErrors[i] + marginOfErrors[j];
if( roundUpFactor < sumMargin) {
newVals[i] = newVals[i] + 1;
newVals[j] = newVals[j] - 1;
marginOfErrors[i] = newVals[i] && Math.abs( orig[i] - newVals[i] ) / orig[i];
marginOfErrors[j] = newVals[j] && Math.abs( orig[j] - newVals[j] ) / orig[j];
}
if( roundDownFactor < sumMargin ) {
newVals[i] = newVals[i] - 1;
newVals[j] = newVals[j] + 1;
marginOfErrors[i] = newVals[i] && Math.abs( orig[i] - newVals[i] ) / orig[i];
marginOfErrors[j] = newVals[j] && Math.abs( orig[j] - newVals[j] ) / orig[j];
}
}
}
function errorFactor( oldNum, newNum ) {
return Math.abs( oldNum - newNum ) / oldNum;
}
return newVals;
}
func([16.666, 16.666, 16.666, 16.666, 16.666, 16.666], 100); // => [16, 16, 17, 17, 17, 17]
func([33.333, 33.333, 33.333], 100); // => [34, 33, 33]
func([33.3, 33.3, 33.3, 0.1], 100); // => [34, 33, 33, 0]
func([13.25, 47.25, 11.25, 28.25], 100 ); // => [13, 48, 11, 28]
func( [25.5, 25.5, 25.5, 23.5], 100 ); // => [25, 25, 26, 24]
最后一件事，我使用问题中最初给出的数字运行函数，与期望的输出进行比较
func([13.626332, 47.989636, 9.596008, 28.788024], 100); // => [48, 29, 13, 10]
这与问题想要的不同=>[48,29,14,9]。我无法理解这一点，直到我看了总误差范围
-------------------------------------------------
| original | question | % diff | mine | % diff |
-------------------------------------------------
| 13.626332 | 14 | 2.74% | 13 | 4.5% |
| 47.989636 | 48 | 0.02% | 48 | 0.02% |
| 9.596008 | 9 | 6.2% | 10 | 4.2% |
| 28.788024 | 29 | 0.7% | 29 | 0.7% |
-------------------------------------------------
| Totals | 100 | 9.66% | 100 | 9.43% |
-------------------------------------------------
从本质上讲，我的函数的结果实际上引入了最少的误差。
小提琴在这里
