During WW II did some of the classes at USMA and USNA graduate and go to war in less than 4 years? IIRC the class of 1943 graduated a year early in 1942.
To answer your question:
Per Wikipeda as to the USMA, “The Class of 1943 was redesignated the Class of January 1943 and graduated six months early. Subsequent classes, from June 1943 through 1947, graduated in three years.”