HDU 5044 - Tree (树链剖分)

感觉一百年没发题解了。
这两天在吴神的嘲讽下终于去做了一年半前就准备学的树剖(:3」∠)
然后随便发个模板题代码吧，证明我还是活着的。

思路

不能用线段树维护，用扫描线的方式，两个端点加减，然后扫一遍。

代码

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#define LL long long
#define ULL unsigned long long
#define SZ(x) (int)x.size()
#define lowbit(x) ((x) & (-x))
#define MP(a, b) make_pair(a, b)
#define MS(p, num) memset(p, num, sizeof(p))
#define PB push_back
#define X first
#define Y second
#define ROP freopen("input.txt", "r", stdin);
#define MID(a, b) (a + ((b - a) >> 1))
#define LC rt << 1, l, mid
#define RC rt << 1|1, mid + 1, r
#define LRT rt << 1
#define RRT rt << 1|1
#define FOR(i, a, b) for (int i=(a); (i) < (b); (i)++)
#define FOOR(i, a, b) for (int i = (a); (i)<=(b); (i)++)
const double PI = acos(-1.0);
const int INF = 0x3f3f3f3f;
const double eps = 1e-8;
const int MAXN = 1e5 + 10;
const int MOD = 1e9 + 7;
const int dir[][2] = { {-1, 0}, {1, 0}, {0, -1}, {0, 1} };
//const int seed = 131;
int cases = 0;
typedef std::pair<int, int> pii;

struct Edge {
    int v, next;
    Edge(int _v, int _next) : v(_v), next(_next){}
};

int id[MAXN], son[MAXN], sz[MAXN], fa[MAXN], top[MAXN], head[MAXN], from[MAXN], to[MAXN], depth[MAXN];
LL ans[2][MAXN], add[2][MAXN];
int n, cnt;
std::vector edges;

void update(int l, int r, int w, int type) {
    ans[type][l] += w;
    ans[type][r + 1] -= w;
}

void change(int u, int v, int w, int type) {
    while (top[u] != top[v]) {
        if (depth[top[u]] < depth[top[v]]) std::swap(u, v);
        update(id[top[u]], id[u], w, type);
        u = fa[top[u]];
    }
    if (depth[u] > depth[v]) std::swap(u, v);
    if (type == 0) update(id[u], id[v], w, type);
    else if (u != v) update(id[son[u]], id[v], w, type);
}

void addEdge(int u, int v) {
    edges.push_back(Edge(v, head[u]));
    head[u] = edges.size() - 1;
}

void dfs1(int u, int pre, int dep) {
    fa[u] = pre; sz[u] = 1; son[u] = 0; depth[u] = dep;
    for (int i = head[u]; ~i; i = edges[i].next) {
        int v = edges[i].v;
        if (v == pre) continue;
        dfs1(v, u, dep + 1);
        sz[u] += sz[v];
        if (sz[v] > sz[son[u]]) son[u] = v;
    }
}

void dfs2(int u, int pre) {
    id[u] = ++cnt; top[u] = pre;
    if (son[u]) dfs2(son[u], pre);
    for (int i = head[u]; ~i; i = edges[i].next) {
        int v = edges[i].v;
        if (v != fa[u] && v != son[u]) dfs2(v, v);
    }
}

void init() {
    edges.clear();
    printf("Case #%d:\n", ++cases);
    cnt = 0;
    MS(ans, 0);
    MS(head, -1);
}

void getAns() {
    for (int i = 1; i <= n; ++i) {
        ans[0][i] += ans[0][i - 1];
        ans[1][i] += ans[1][i - 1];
    }
}

int main() {
    //ROP;
    int T;
    scanf("%d", &T);
    while (T--) {
        init();
        int m;
        scanf("%d%d", &n, &m);
        for (int i = 1; i < n; ++i) {
            scanf("%d%d", &from[i], &to[i]);
            addEdge(from[i], to[i]);
            addEdge(to[i], from[i]);
        }

        dfs1(1, 0, 0);
        dfs2(1, 1);

        for (int i = 1; i < n; ++i) {
            if (depth[from[i]] < depth[to[i]]) std::swap(from[i], to[i]);
        }

        char cmd[10];
        while (m--) {
            int u, v, w;
            scanf("%s%d%d%d", cmd, &u, &v, &w);
            if (cmd[3] == '1') change(u, v, w, 0);
            else change(u, v, w, 1);
        }
        getAns();

        for (int i = 1; i <= n; ++i) printf("%I64d%c", ans[0][id[i]], i == n ? '\n' : ' ');
        for (int i = 1; i < n; ++i) printf("%I64d%c", ans[1][id[from[i]]], i == n - 1 ? '\n' : ' ');
        if (n == 1) puts("");

    }
    return 0;
}