Dodgson's method of swaps needed to make him a winner) is an NP-complete problem by reduction from Exact Cover by 3-Sets (X3C). Dodgson's method Dodgson's method is an electoral system proposed by the author, mathematician and logician Charles Dodgson, better known as Lewis Carroll. The method is to extend the Condorcet method by swapping candidates until a Condorcet winner is found. The winner is the candidate which requires the minimum number of swaps. Dodgson proposed this voting scheme in his 1876 work "A method of taking votes on more than two issues". Given an integer "k" and an election, it is NP-complete
Charles Dodgson (bishop) Charles Dodgson (bishop) Charles Dodgson ( – 21 January 1795) was an English Anglican cleric who served in the Church of Ireland as the Bishop of Ossory (1765–1775) then Bishop of Elphin (1775–1795). Dodgson was born in Howden, Yorkshire. His date of birth is not recorded; he was baptised on 10 January 1722. His father, Christopher Dodgson (1696–1750), was the curate there. Charles Dodgson was educated at Westminster School and St. John's College, Cambridge. After ordination, he was appointed to the parish of Bintry, Norfolk in 1746. He moved to the north of England, keeping a school at Stanwix in