72 lines
1.3 KiB
Go
72 lines
1.3 KiB
Go
package matrix
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import (
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"errors"
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"strconv"
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"strings"
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)
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// Matrix is a grid of ints
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type Matrix struct {
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vals [][]int
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}
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type Pair [2]int
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// New creates a new Matrix from a string of numbers
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func New(in string) (*Matrix, error) {
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ret := Matrix{}
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rows := strings.Split(in, "\n")
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for i := range rows {
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flds := strings.Fields(rows[i])
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var ints []int
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for j := range flds {
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if v, err := strconv.Atoi(flds[j]); err != nil {
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return &ret, err
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} else {
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ints = append(ints, v)
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}
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}
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ret.vals = append(ret.vals, ints)
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}
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numInRow := -1
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for i := range ret.vals {
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if numInRow != -1 {
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if len(ret.vals[i]) != numInRow {
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return &ret, errors.New("All rows must be equal length")
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}
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}
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numInRow = len(ret.vals[i])
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}
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return &ret, nil
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}
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// Saddle finds all Saddle Points in the matrix
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func (m *Matrix) Saddle() []Pair {
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var ret []Pair
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for i := range m.vals {
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for j := range m.vals[i] {
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val := m.vals[i][j]
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// Check if i,j is a saddle point
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// (Highest in row, lowest in col)
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colTest, rowTest := true, true
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for k := range m.vals {
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if m.vals[k][j] < val {
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colTest = false
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break
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}
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}
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for k := range m.vals[i] {
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if m.vals[i][k] > val {
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rowTest = false
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break
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}
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}
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if colTest && rowTest {
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ret = append(ret, Pair{i, j})
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}
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}
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}
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return ret
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}
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