求某合约N周期的最高点、最低点的连续折线，要求：如果极值点没有变化，则序列变量（序列变量必须连续的吗？）不赋值，有变化时需要赋值，如何实现，求各位大神不吝赐教，拜谢！

If (Highest(High[1], periodSingle) <>Highest(High[2], periodSingle))

{

highestCrest = Highest(High[1], periodSingle);

PlotAuto(\"highestCrest: \", highestCrest, 0, Red);

}

If (Lowest(Low[1], periodSingle), RN) <> Round(Lowest(Low[2], periodSingle))

{

lowestTrough = Lowest(Low[1], periodSingle);

PlotAuto(\"lowestTrough: \", lowestTrough, 0, Cyan);

}

Commentary(\"highestCrest: \" + Text(highestCrest));

Commentary(\"highestCrest[1]: \" + Text(highestCrest[1]));

Commentary(\"highestCrest[2]: \" + Text(highestCrest[2]));

Commentary(\"lowestTrough: \" + Text(lowestTrough));

Commentary(\"lowestTrough[1]: \" + Text(lowestTrough[1]));

Commentary(\"lowestTrough[2]: \" + Text(lowestTrough[2]));

结果仍然有相等的数值，即highestCrest = highestCrest[1] = highestCrest[2]，为什么呢？