Day289

README.md

@@ -300,6 +300,7 @@ problems from
 * [Day 286](https://github.com/vaskoz/dailycodingproblem-go/issues/585)
 * [Day 287](https://github.com/vaskoz/dailycodingproblem-go/issues/587)
 * [Day 288](https://github.com/vaskoz/dailycodingproblem-go/issues/590)
+* [Day 289](https://github.com/vaskoz/dailycodingproblem-go/issues/593)
 * [Day 290](https://github.com/vaskoz/dailycodingproblem-go/issues/594)
 * [Day 291](https://github.com/vaskoz/dailycodingproblem-go/issues/596)
 * [Day 292](https://github.com/vaskoz/dailycodingproblem-go/issues/598)

day289/problem.go

@@ -0,0 +1,13 @@
+package day289
+
+// CanFirstPlayerForceWinNimGame answers if the first player
+// can force a win with the given heap configuration.
+func CanFirstPlayerForceWinNimGame(heaps []int) bool {
+	sum := 0
+
+	for _, heap := range heaps {
+		sum ^= heap
+	}
+
+	return sum != 0
+}

day289/problem_test.go

@@ -0,0 +1,35 @@
+package day289
+
+import "testing"
+
+// nolint
+var testcases = []struct {
+	heaps     []int
+	forcedWin bool
+}{
+	{[]int{3, 4, 5}, true},
+	{[]int{1, 2, 3}, false},
+	{[]int{1, 4, 5}, false},
+	{[]int{1, 6, 7}, false},
+	{[]int{5, 9, 12}, false},
+	{[]int{1, 2, 4, 7}, false},
+	{[]int{1, 2, 4, 6}, true},
+}
+
+func TestCanFirstPlayerForceWinNimGame(t *testing.T) {
+	t.Parallel()
+
+	for _, tc := range testcases {
+		if res := CanFirstPlayerForceWinNimGame(tc.heaps); res != tc.forcedWin {
+			t.Errorf("Expected %v, got %v", tc.forcedWin, res)
+		}
+	}
+}
+
+func BenchmarkCanFirstPlayerForceWinNimGame(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		for _, tc := range testcases {
+			CanFirstPlayerForceWinNimGame(tc.heaps)
+		}
+	}
+}