Nikon A1000 has a
16.0MP 1/2.3 (6.17 x 4.55 mm ) sized BSI-CMOS sensor . On the other hand, Nikon L100 has a
10.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor .
Nikon A1000's sensor provides 6MP more than Nikon L100's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the A1000 and L100 sensor size comparison.
Nikon A1000 and Nikon L100 have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.