A schematic diagram of a water tank system is shown in Figure $3,$ consisting of $5$ floaters. When there is water, terminals $2$ and $3$ are connected, and when there is no water, terminals $1$ and $2$ are connected. When AB is powered, the display screen is illuminated. The voltage parameters are $1\mathrm{.}2$ to $1\mathrm{.}8$V$,$ and the current parameters are $3$ to $5$mA$.$

The hardware circuit of the system is illustrated in Figure $5.$ KOI, KIL, K$21,$ K$31,$ K$41$ are connected to the $74$SL$245$ circuit, while K$02,$ K$12,$ K$22,$ K$32,$ K$42$ are grounded. The A end of the display is connected to the $74$LS$273$ circuit. The CS$0$ address is $40$H$,$ and the CS$1$ address is $41$H

Analyze and calculate the optimal resistor parameters based on the given information, draw a flowchart and write a program. $($Requirement: Ensure that the number of water levels in the water tank matches the number displayed on the LED display.$)$