Syncing

go/saddle-points/saddle.go

@@ -2,7 +2,6 @@ package matrix
 
 import (
 	"errors"
-	"fmt"
 	"strconv"
 	"strings"
 )
@@ -42,68 +41,31 @@ func New(in string) (*Matrix, error) {
 	return &ret, nil
 }
 
+// Saddle finds all Saddle Points in the matrix
 func (m *Matrix) Saddle() []Pair {
 	var ret []Pair
-	// We're going to get a list of coords for row highs
-	// then compare that to a list of coords for col lows
-	var testRows []Pair
 	for i := range m.vals {
-		testRows = append(testRows, Pair{i, m.findRowHigh(i)})
-	}
-	fmt.Println(testRows)
-	return ret
-	for j := range m.vals[0] {
-		v := Pair{m.findColLow(j), j}
-		// If this pair is in testRows, it's a saddle point
-		for i := range testRows {
-			if v[0] == testRows[i][0] && v[1] == testRows[i][1] {
-				ret = append(ret, v)
+		for j := range m.vals[i] {
+			val := m.vals[i][j]
+			// Check if i,j is a saddle point
+			// (Highest in row, lowest in col)
+			colTest, rowTest := true, true
+			for k := range m.vals {
+				if m.vals[k][j] < val {
+					colTest = false
+					break
+				}
+			}
+			for k := range m.vals[i] {
+				if m.vals[i][k] > val {
+					rowTest = false
+					break
+				}
+			}
+			if colTest && rowTest {
+				ret = append(ret, Pair{i, j})
 			}
 		}
 	}
 	return ret
 }
-
-// Cols returns the values of the cols in the matrix
-func (m *Matrix) Cols() [][]int {
-	var ret [][]int
-	for i := range m.vals[0] {
-		var row []int
-		for j := range m.vals {
-			row = append(row, m.vals[j][i])
-		}
-		ret = append(ret, row)
-	}
-	return ret
-}
-
-// findColLow finds the lowest value in a column
-func (m *Matrix) findColLow(c int) int {
-	cols := m.Cols()
-	var idx int
-	val := -1
-	if c >= 0 && c < len(cols) {
-		for i := range cols[c] {
-			if cols[c][i] < val || val == -1 {
-				val = cols[c][i]
-				idx = i
-			}
-		}
-	}
-	return idx
-}
-
-// findColLow finds the lowest value in a column
-func (m *Matrix) findRowHigh(r int) int {
-	var idx int
-	val := -1
-	if r >= 0 && r < len(m.vals) {
-		for i := range m.vals[r] {
-			if m.vals[r][i] < val || val == -1 {
-				val = m.vals[r][i]
-				idx = i
-			}
-		}
-	}
-	return idx
-}