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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#287128#7755. Game on a ForestMax_s_xaMWA 1ms8420kbC++143.5kb2023-12-19 18:57:102023-12-19 18:57:11

Judging History

你现在查看的是最新测评结果

  • [2023-12-19 18:57:11]
  • 评测
  • 测评结果:WA
  • 用时:1ms
  • 内存:8420kb
  • [2023-12-19 18:57:10]
  • 提交

answer

#include <iostream>
#include <vector>

typedef long long ll;
typedef double lf;

// #define DEBUG 1
struct IO
{
    #define MAXSIZE (1 << 20)
    #define isdigit(x) (x >= '0' && x <= '9')
    char buf[MAXSIZE], *p1, *p2;
    char pbuf[MAXSIZE], *pp;
    #if DEBUG
    #else
    IO() : p1(buf), p2(buf), pp(pbuf) {}
    ~IO() {fwrite(pbuf, 1, pp - pbuf, stdout);}
    #endif
    #define gc() (p1 == p2 && (p2 = (p1 = buf) + fread(buf, 1, MAXSIZE, stdin), p1 == p2) ? ' ' : *p1++)
    #define blank(x) (x == ' ' || x == '\n' || x == '\r' || x == '\t')

    template <typename T>
    void Read(T &x)
    {
        #if DEBUG
        std::cin >> x;
        #else
        bool sign = 0; char ch = gc(); x = 0;
        for (; !isdigit(ch); ch = gc())
            if (ch == '-') sign = 1;
        for (; isdigit(ch); ch = gc()) x = x * 10 + (ch ^ 48);
        if (sign) x = -x;
        #endif
    }
    void Read(char *s)
    {
        #if DEBUG
        std::cin >> s;
        #else
        char ch = gc();
        for (; blank(ch); ch = gc());
        for (; !blank(ch); ch = gc()) *s++ = ch;
        *s = 0;
        #endif
    }
    void Read(char &c) {for (c = gc(); blank(c); c = gc());}

    void Push(const char &c)
    {
        #if DEBUG
        putchar(c);
        #else
        if (pp - pbuf == MAXSIZE) fwrite(pbuf, 1, MAXSIZE, stdout), pp = pbuf;
        *pp++ = c;
        #endif
    }
    template <typename T>
    void Write(T x)
    {
        if (x < 0) x = -x, Push('-');
        static T sta[35];
        int top = 0;
        do sta[top++] = x % 10, x /= 10; while (x);
        while (top) Push(sta[--top] ^ 48);
    }
    template <typename T>
    void Write(T x, char lst) {Write(x), Push(lst);}
} IO;
#define Read(x) IO.Read(x)
#define Write(x, y) IO.Write(x, y)
#define Put(x) IO.Push(x)

using namespace std;

const int MAXN = 1e5 + 10;

int n, m;
struct Edge
{
    int u, v;
}g[MAXN];
vector <int> e[MAXN];

int fa[MAXN], sz[MAXN], rt[MAXN];
void DFS(int u, int t, int tt)
{
    fa[u] = t, sz[u] = 1, rt[u] = tt;
    for (auto v : e[u])
        if (v != t) DFS(v, u, tt), sz[u] += sz[v];
}
int cnt[2];

int main()
{
    #if DEBUG
    #else
    ios::sync_with_stdio(0), cin.tie(0);
    #endif
    Read(n), Read(m);
    for (int i = 1; i <= m; i++) Read(g[i].u), Read(g[i].v), e[g[i].u].push_back(g[i].v), e[g[i].v].push_back(g[i].u);
    for (int i = 1; i <= n; i++)
        if (!sz[i]) DFS(i, 0, i);
    for (int i = 1; i <= n; i++)
        if (rt[i] == i) cnt[sz[i] & 1]++;
    int ans = 0;
    for (int i = 1; i <= m; i++)
    {
        cnt[sz[rt[g[i].u]] & 1]--;
        if (fa[g[i].u] == g[i].v) cnt[sz[g[i].u] & 1]++, cnt[(sz[rt[g[i].u]] - sz[g[i].u]) & 1]++;
        else cnt[sz[g[i].v] & 1]++, cnt[(sz[rt[g[i].u]] - sz[g[i].v]) & 1]++;
        if (!(cnt[0] & 1) && !(cnt[1] & 1)) ans++;
        if (fa[g[i].u] == g[i].v) cnt[sz[g[i].u] & 1]--, cnt[(sz[rt[g[i].u]] - sz[g[i].u]) & 1]--;
        else cnt[sz[g[i].v] & 1]--, cnt[(sz[rt[g[i].u]] - sz[g[i].v]) & 1]--;
        cnt[sz[rt[g[i].u]] & 1]++;
    }
    for (int i = 1; i <= n; i++)
    {
        cnt[sz[rt[i]] & 1]--;
        for (auto v : e[i])
            if (v == fa[i]) cnt[(sz[rt[i]] - sz[i]) & 1]++;
            else cnt[sz[v]]++;
        if (!(cnt[0] & 1) && !(cnt[1] & 1)) ans++;
        for (auto v : e[i])
            if (v == fa[i]) cnt[(sz[rt[i]] - sz[i]) & 1]--;
            else cnt[sz[v]]--;
        cnt[sz[rt[i]] & 1]++;
    }
    cout << ans << "\n";
    return 0;
}

Details

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Test #1:

score: 100
Accepted
time: 1ms
memory: 8080kb

input:

3 1
1 2

output:

2

result:

ok 1 number(s): "2"

Test #2:

score: -100
Wrong Answer
time: 1ms
memory: 8420kb

input:

4 3
1 2
2 3
3 4

output:

4

result:

wrong answer 1st numbers differ - expected: '3', found: '4'