1 files changed, 63 insertions(+), 0 deletions(-)

M election/voter.go

@@ 7,6 7,7 @@ import (
 	"fmt"
 	"io"
 	"math/big"
+	"sort"
 	"sync"
 	"time"
 


@@ 290,4 291,66 @@ func printResults(result []byte, candidates []Candidate) {
 			}
 		}
 	}
+
+	// Schulze method computation
+	// https://en.wikipedia.org/wiki/Schulze_method#Implementation
+	min := func(x, y int) int {
+		if x < y {
+			return x
+		}
+		return y
+	}
+	max := func(x, y int) int {
+		if x > y {
+			return x
+		}
+		return y
+	}
+	p := make(map[int]map[int]int)
+	for i := range candidates {
+		for j := range candidates {
+			if i != j {
+				if p[i] == nil {
+					p[i] = make(map[int]int)
+				}
+				if result[i*n+j] > result[j*n+i] {
+					p[i][j] = int(result[i*n+j])
+				} else {
+					p[i][j] = 0
+				}
+			}
+		}
+	}
+	for i := range candidates {
+		for j := range candidates {
+			if i != j {
+				for k := range candidates {
+					if i != k && j != k {
+						p[j][k] = max(p[j][k], min(p[j][i], p[i][k]))
+					}
+				}
+			}
+		}
+	}
+	order := []int{}
+	for i := range candidates {
+		k := sort.Search(len(order), func(j int) bool {
+			return p[i][order[j]] > p[order[j]][i]
+		})
+		newOrder := make([]int, len(order)+1)
+		copy(newOrder[:k], order[:k])
+		newOrder[k] = i
+		copy(newOrder[k+1:], order[k:])
+		order = newOrder
+	}
+	fmt.Printf("\n=== Schulze Method Ranking ===\n")
+	for i:= 0; i < len(order); i++ {
+		rank := i+1 // don't want 0th place
+		fmt.Printf("%d) %s\n", rank, candidates[order[i]])
+		// candidates that are tied get the same rank
+		for i+1 < len(order) && p[order[i]][order[i+1]] == p[order[i+1]][order[i]] {
+			fmt.Printf("%d) %s\n", rank, candidates[order[i+1]])
+			i++
+		}
+	}
 }