add new solutions

solutions/23/q2352/solution.go

@@ -0,0 +1,39 @@
+package q2352
+
+import "strings"
+
+func index(grid [][]int, col bool, i int) string {
+	b := strings.Builder{}
+	b.Grow(len(grid) * 3)
+	for j := range grid {
+		var num int
+		switch {
+		case col: // ith col
+			num = grid[j][i]
+		default: // ith row
+			num = grid[i][j]
+		}
+
+		for range 3 {
+			b.WriteByte(byte(num % 256))
+			num >>= 8
+		}
+	}
+	return b.String()
+}
+
+func equalPairs(grid [][]int) int {
+	idx := make(map[string]int, len(grid))
+	nEq := 0
+	for row := range grid {
+		s := index(grid, false, row)
+		idx[s]++
+	}
+	for col := range grid {
+		s := index(grid, true, col)
+		nEq += idx[s]
+	}
+	return nEq
+}
+
+var _ = equalPairs