The last time BTC halved, the price went up a few percent for a couple weeks after it happened, then it dropped a bit and took three months to recover to what it was before the halving. The last time LTC halved, the price held pretty steady for a couple months before spiking up. If mining a single Bitcoin today costs 7200 USD of super computer power and electricuty, it will cost 14200 USD after. So either price increases or hashrate drops to compensate for it.