Ernest Lehman, a noted Hollywood screenwriter whose work included classic films of the 1950's and 60's like "North by Northwest," "Sweet Smell of Success" and "The Sound of Music," died on Saturday in Los Angeles. He was 89 and lived in Los Angeles.The apparent cause was a heart attack, his wife, Laurie, said.One of the best-known screenwriters in Hollywood in the postwar years, Mr. Lehman worked with many of the most prominent directors of the period, including Alfred Hitchcock and Billy Wilder. A master of adaptation, he wrote or was a co-writer of film scripts for several Broadway musicals, including...