aaa

src/codeforces/set1/set19/set197/set1970/c1/problem.md

@@ -0,0 +1,6 @@
+Ron and Hermione are playing a game on a tree of 𝑛
+ nodes that are initially inactive. This tree is special because it has exactly two leaves. It can thus be seen as an array. The game consists of 𝑡
+ rounds, each of which starts with a stone on exactly one node, which is considered as activated. A move consists of picking an inactive neighbor of the node with a stone on it and moving the stone there (thus activating this neighbor). Ron makes the first move, after which he alternates with Hermione until no valid move is available. The player that cannot make a move loses the round. If both players play optimally, who wins each round of this game?
+
+Note that all the rounds are played with the same tree; only the starting node changes. Moreover, after each round, all active nodes are considered inactive again.
+

src/codeforces/set1/set19/set197/set1970/c1/solution.go

@@ -0,0 +1,164 @@
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"os"
+)
+
+func main() {
+	reader := bufio.NewReader(os.Stdin)
+
+	n, m := readTwoNums(reader)
+	edges := make([][]int, n-1)
+	for i := 0; i < n-1; i++ {
+		edges[i] = readNNums(reader, 2)
+	}
+
+	rounds := make([]int, m)
+	for i := 0; i < m; i++ {
+		rounds[i] = readNum(reader)
+	}
+	ans := solve(n, edges, rounds)
+
+	var buf bytes.Buffer
+
+	for _, x := range ans {
+		buf.WriteString(x)
+		buf.WriteByte('\n')
+	}
+
+	fmt.Print(buf.String())
+}
+func readString(reader *bufio.Reader) string {
+	s, _ := reader.ReadString('\n')
+	for i := 0; i < len(s); i++ {
+		if s[i] == '\n' || s[i] == '\r' {
+			return s[:i]
+		}
+	}
+	return s
+}
+
+func readInt(bytes []byte, from int, val *int) int {
+	i := from
+	sign := 1
+	if bytes[i] == '-' {
+		sign = -1
+		i++
+	}
+	tmp := 0
+	for i < len(bytes) && bytes[i] >= '0' && bytes[i] <= '9' {
+		tmp = tmp*10 + int(bytes[i]-'0')
+		i++
+	}
+	*val = tmp * sign
+	return i
+}
+
+func readNum(reader *bufio.Reader) (a int) {
+	bs, _ := reader.ReadBytes('\n')
+	readInt(bs, 0, &a)
+	return
+}
+
+func readTwoNums(reader *bufio.Reader) (a int, b int) {
+	res := readNNums(reader, 2)
+	a, b = res[0], res[1]
+	return
+}
+
+func readThreeNums(reader *bufio.Reader) (a int, b int, c int) {
+	res := readNNums(reader, 3)
+	a, b, c = res[0], res[1], res[2]
+	return
+}
+
+func readNNums(reader *bufio.Reader, n int) []int {
+	res := make([]int, n)
+	x := 0
+	bs, _ := reader.ReadBytes('\n')
+	for i := 0; i < n; i++ {
+		for x < len(bs) && (bs[x] < '0' || bs[x] > '9') && bs[x] != '-' {
+			x++
+		}
+		x = readInt(bs, x, &res[i])
+	}
+	return res
+}
+
+const Ron = "Ron"
+const Hermione = "Hermione"
+
+func solve(n int, edges [][]int, rounds []int) []string {
+	deg := make([]int, n)
+	g := NewGraph(n, n*2)
+	for _, cur := range edges {
+		u, v := cur[0]-1, cur[1]-1
+		deg[u]++
+		deg[v]++
+		g.AddEdge(u, v)
+		g.AddEdge(v, u)
+	}
+
+	first := 0
+	for i := 0; i < n; i++ {
+		if deg[i] == 1 {
+			first = i
+			break
+		}
+	}
+
+	pos := make([]int, n)
+
+	var dfs func(p int, u int)
+
+	dfs = func(p int, u int) {
+		for i := g.nodes[u]; i > 0; i = g.next[i] {
+			v := g.to[i]
+			if p != v {
+				pos[v] = pos[u] + 1
+				dfs(u, v)
+			}
+		}
+	}
+
+	dfs(-1, first)
+
+	ans := make([]string, len(rounds))
+
+	for i, u := range rounds {
+		u--
+		x := pos[u]
+		y := n - 1 - x
+		if x&1 == 1 || y&1 == 1 {
+			ans[i] = Ron
+		} else {
+			ans[i] = Hermione
+		}
+	}
+
+	return ans
+}
+
+type Graph struct {
+	nodes []int
+	next  []int
+	to    []int
+	cur   int
+}
+
+func NewGraph(n int, e int) *Graph {
+	nodes := make([]int, n)
+	next := make([]int, e)
+	to := make([]int, e)
+	return &Graph{nodes, next, to, 0}
+}
+
+func (g *Graph) AddEdge(u, v int) {
+	g.cur++
+	g.next[g.cur] = g.nodes[u]
+	g.nodes[u] = g.cur
+	g.to[g.cur] = v
+}

src/codeforces/set1/set19/set197/set1970/c1/solution_test.go

@@ -0,0 +1,40 @@
+package main
+
+import (
+	"reflect"
+	"testing"
+)
+
+func runSample(t *testing.T, n int, edges [][]int, rounds []int, expect []string) {
+	res := solve(n, edges, rounds)
+
+	if !reflect.DeepEqual(res, expect) {
+		t.Fatalf("Sample expect %v, but got %v", expect, res)
+	}
+}
+
+func TestSample1(t *testing.T) {
+	n := 3
+	edges := [][]int{
+		{2, 3},
+		{3, 1},
+	}
+	rounds := []int{3}
+	expect := []string{Ron}
+
+	runSample(t, n, edges, rounds, expect)
+}
+
+func TestSample2(t *testing.T) {
+	n := 5
+	edges := [][]int{
+		{1, 2},
+		{2, 3},
+		{3, 4},
+		{4, 5},
+	}
+	rounds := []int{5}
+	expect := []string{Hermione}
+
+	runSample(t, n, edges, rounds, expect)
+}