上面的都过了，vijos也ac了，交上去还WA，无语。。。。。那个大牛帮下
#include<iostream>
using namespace std;
int fa[500001], flag[500001];

void Initset(int n) {
    for (int i = 1; i <= n; i++) {
        fa[i] = i;
        flag[i] = 0;
    }
}

int find(int x) {
    int t = fa[x];
    if (fa[x] != x) {
        fa[x] = find(fa[x]);
        flag[x] = (flag[x] + flag[t] + 1) % 3 - 1;
    }
    return fa[x];
}

int unin(int a, int x, int y) {
    int m = find(x), n = find(y);
    if (m == n) {
        if ((flag[x] - flag[y] + 3) % 3 != a - 1)return 1;
    } else fa[m] = n, flag[m] = (flag[y] - flag[x] + a) % 3 - 1;
    return 0;
}

int main() {
    int n, k, a, x, y, re;
    while (cin >> n >> k) {
        Initset(n);
        re = 0;
        while (k--) {
            cin >> a >> x >> y;
            if (x > n || y > n || (a == 2 && x == y) || unin(a, x, y)) re++;
        }
        cout << re << endl;
    }
}

• 我前面和你一样，无线wa。还是理解不深 (206) liuyu523115237 2012-04-23 22:35:25