BZOJ

BZOJ 3673 3674

3673
3674

使用线段树作为可持久化数据结构维护朴素并查集中的fa数组

用到的都是可持久化线段树的基本操作

3674还需要路径压缩

用3674的代码改掉强制在线交到3673上过了以后去交3674，但是忘了把强制在线改回来……结果直接过了……WNM


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//3674
#include <bits/stdc++.h>

struct seg {
    int l, r, lc, rc, fa;
} s[200010 * 20 * 2];

int root[200010], tot = 0;

int build(int l, int r) {
    int t = ++ tot;
    s[t].l = l;
    s[t].r = r;
    if (l == r) {
        s[tot].fa = l;
        return t;
    }
    int mid = l + r >> 1;
    s[t].lc = build(l, mid);
    s[t].rc = build(mid + 1, r);
    return t;
}

int findfa(int t, int k) {
    if (s[t].l == s[t].r)
        return s[t].fa;
    int mid = s[t].l + s[t].r >> 1;
    if (k <= mid)
        return findfa(s[t].lc, k);
    else
        return findfa(s[t].rc, k);
}

void insert(int &t, int pt, int k, int fa) {
    t = ++ tot;
    s[t] = s[pt];
    if (s[t].l == s[t].r) {
        s[t].fa = fa;
        return;
    }
    int mid = s[t].l + s[t].r >> 1;
    if (k <= mid)
        insert(s[t].lc, s[pt].lc, k, fa);
    else
        insert(s[t].rc, s[pt].rc, k, fa);
}

int getfa(int i, int t) {
    int fa = findfa(root[i], t);
    if (fa == t)
        return t;
    int faa = getfa(i, fa);
    insert(root[i], root[i], t, faa);
    return faa;
}

int main() {
    int n, m;
    scanf("%d%d", &n, &m);
    root[0] = build(1, n);
    int a, b, c;
    int ans = 0;
    for (int i = 1; i <= m; i ++) {
        scanf("%d", &c);
        if (c == 1) {
            scanf("%d%d", &a, &b);
            a ^= ans, b ^= ans;
            root[i] = root[i - 1];
            insert(root[i], root[i - 1], getfa(i, a), getfa(i, b));
        }
        if (c == 2) {
            scanf("%d", &a);
            a ^= ans;
            root[i] = root[a];
        }
        if (c == 3) {
            scanf("%d%d", &a, &b);
            a ^= ans, b ^= ans;
            root[i] = root[i - 1];
            if (getfa(i, a) == getfa(i, b))
                ans = 1;
            else
                ans = 0;
            printf("%d\n", ans);
            ans = 0; // <- 不把这一行删掉也tm能过
        }
    }
    return 0;
}

3673的代码就不贴了