POJ 2763 housewife Wind (tree chain split + single point query + interval modification)

Title Link: http://poj.org/problem?id=2763

Test instructions: Give a number, the edge between the right value, and then two operations, the first: the weight of any two points and, second, modify the weight of two points on the tree.

Puzzle: Simple tree-chain split.

#include <iostream> #include <cstdio> #include <cstring>using namespace std;const int M = 1e5 + 10;struct Edge {int V, next;} Edge[m << 1];int head[m], e;int top[m];int fa[m];int num[m];int p[m];int fp[m];int deep[m];int son[M];int pos;void    Init () {memset (head,-1, sizeof (head));    Memset (son,-1, sizeof (son));    e = 0; pos = 1;}    void Add (int u, int v) {edge[e].v = v;    Edge[e].next = Head[u]; Head[u] = e++;}    void dfs1 (int u, int pre, int d) {deep[u] = D;    Fa[u] = pre;    Num[u] = 1;        for (int i = head[u]; i =-1; i = edge[i].next) {int v = EDGE[I].V;            if (v! = Pre) {dfs1 (V, u, D + 1);            Num[u] + = Num[v];            if (son[u] = = 1 | | num[son[u]] < Num[v]) {Son[u] = V;    }}}}void GetPos (int u, int sp) {top[u] = SP;    P[u] = pos++;    Fp[p[u]] = u;    if (son[u] = =-1) return;    GetPos (Son[u], SP); for (int i = head[u]; I! =-1; i = EDGE[I].NEXT) {int v = EDGE[I].V;        if (v = son[u] && v! = Fa[u]) {GetPos (V, v); }}}struct TnT {int L, r, sum;} T[m << 2];int ed[m][3];void pushup (int i) {t[i].sum = t[i << 1].sum + t[(i << 1) | 1].sum;}    void build (int l, int r, int i) {int mid = (L + r) >> 1;    T[I].L = L, T[I].R = r, t[i].sum = 0;    if (L = = r) {return;    } build (L, Mid, I << 1);    Build (mid + 1, R, (i << 1) | 1); Pushup (i);}    void Updata (int pos, int i, int ad) {int mid = (t[i].l + t[i].r) >> 1;        if (t[i].l = = T[I].R && T[I].L = = pos) {t[i].sum = AD;    return;    } if (Mid < POS) {Updata (pos, (i << 1) | 1, AD);    } else {Updata (pos, I << 1, AD); } pushup (i);}    int query (int l, int r, int i) {int mid = (t[i].l + t[i].r) >> 1;    if (T[I].L = = L && T[I].R = = r) {return t[i].sum;    } pushup (i); if (mid < L) {return query (L, R, (i << 1) | 1);    } else if (Mid >= R) {return query (L, R, I << 1);    } else {return query (L, Mid, I << 1) + query (mid + 1, R, (i << 1) | 1);    }}int find (int u, int v) {int f1 = Top[u], F2 = top[v];    int tmp = 0;            while (f1! = F2) {if (Deep[f1] < DEEP[F2]) {swap (f1, F2);        Swap (U, v);        } tmp + = query (P[f1], p[u], 1);    U = fa[f1], f1 = Top[u];    } if (U = = v) return tmp;    if (Deep[u] > Deep[v]) Swap (U, v); return tmp + query (P[son[u]], p[v], 1);}    int main () {int n, q, S, CP, U, v;    scanf ("%d%d%d", &n, &q, &s);    Init ();        for (int i = 0; i < n-1; i++) {for (int j = 0; J < 3; J + +) {scanf ("%d", &ed[i][j]);        } Add (Ed[i][0], ed[i][1]);    Add (Ed[i][1], ed[i][0]);    } dfs1 (1, 0, 0);    GetPos (1, 1);    Build (0, POS, 1); for (int i= 0; i < n-1;        i++) {if (deep[ed[i][0]] > deep[ed[i][1]) {swap (ed[i][0], ed[i][1]);    } updata (P[ed[i][1]], 1, ed[i][2]);        } while (q--) {scanf ("%d", &AMP;CP);            if (cp = = 0) {scanf ("%d", &u);            printf ("%d\n", find (S, u));        s = u;            } else {scanf ("%d%d", &u, &v);        Updata (P[ed[u-1][1]], 1, v); }} return 0;}

Poj 2763 Housewife Wind (tree-chain split + single-point query + interval modification)