The LM35 gives 10mV/°C and so at 100°C it will output 1V. A 2V reference and an opamp with an adjustable gain around 2 could be calibrated to give an ADC output of 1023 for a temperature of 102.3°C. The reference could be a zener/resistor combo and this would alleviate the need for a rail to rail opamp.
If you haven't bought the OpAmp yet, look at tip#12: https://www.electro-tech-online.com/custompdfs/2008/08/41215a.pdf
I've never used the on-chip comparators as an OpAmp, so I'm not sure if this method would even give you the voltage swing you need. Might be worth experimenting with it if your PCB is tight for space/money.