Housewife Wind poj2763

LCA+树状数组，用由于dfs序列中同一子树节点是连续的，所以可以用树状数组维护dfs序列到到根的距离。

LCA都忘记咋写了，越来越依赖模板了~~

#include <iostream>#include <cstdio>#include <cstdlib>#include <cmath>#include <queue>#include <algorithm>#include <vector>#include <cstring>#include <stack>#include <cctype>#include <utility>   #include <map>#include <string>  #include <climits> #include <set>#include <string>    #include <sstream>#include <utility>   #include <ctime>using std::priority_queue;using std::vector;using std::swap;using std::stack;using std::sort;using std::max;using std::min;using std::pair;using std::map;using std::string;using std::cin;using std::cout;using std::set;using std::queue;using std::string;using std::istringstream;using std::make_pair;using std::getline;using std::greater;using std::endl;using std::multimap;using std::deque;typedef long long LL;typedef unsigned long long ULL;typedef pair<int, int> PAIR;typedef multimap<int, int> MMAP;const int MAXN(100010);const int SIGMA_SIZE(26);const int MAXM(110);const int MAXE(200010);const int MAXH(19);const int INFI((INT_MAX-1) >> 1);const int MOD(2012);const ULL BASE(31);const ULL LIM(1000000000000000ull);struct EDGE{int v, w, next;};int first[MAXN];EDGE edge[MAXE];int rear;void init(int tn){memset(first, -1, sizeof(first[0])*(tn+1));rear = 0;}void insert(int tu, int tv, int tw){edge[rear].v = tv;edge[rear].w = tw;edge[rear].next = first[tu];first[tu] = rear++;}int sumdist[MAXN];int ind;int poss[MAXN], pose[MAXN];struct LCA{int E[MAXN << 1], dep[MAXN << 1], pos[MAXN];int back;int table[MAXH][MAXN << 1];inline int comp(int op1, int op2){return dep[op1] <= dep[op2]? op1: op2;}void init(){back = 0;ind = 0;dfs(1, 0, 0, -1);for(int i = 1; i <= back; ++i)table[0][i] = i;for(int i = 1; (1 << i) <= back; ++i)for(int j = 1; j+(1 << i)-1 <= back; ++j)table[i][j] = comp(table[i-1][j], table[i-1][j+(1 << (i-1))]);}void dfs(int cur, int d, int dis, int tf){E[++back] = cur;dep[back] = d;pos[cur] = back;sumdist[cur] = dis;poss[cur] = ++ind;for(int i = first[cur]; ~i; i = edge[i].next)if(edge[i].v != tf){dfs(edge[i].v, d+1, dis+edge[i].w, cur);E[++back] = cur;dep[back] = d;}pose[cur] = ind;}int query(int op1, int op2){op1 = pos[op1];op2 = pos[op2];if(op1 > op2)swap(op1, op2);int len = op2-op1+1, temp = 0;while((1 << temp) <= len)++temp;--temp;return E[comp(table[temp][op1], table[temp][op2-(1 << temp)+1])];}};LCA lca;struct FENWICK_TREE{int table[MAXN];int size;void init(int tn){size = tn;memset(table+1, 0, sizeof(table[0])*tn);}inline int lowb(int op){return op&(-op);}int query(int op){int ret = 0;for(int i = op; i >= 1; i -= lowb(i))ret += table[i];return ret;}void add(int op, int value){for(int i = op; i <= size; i += lowb(i))table[i] += value;}};FENWICK_TREE ft;int rec[3][MAXN];int main(){int n, q, s;while(~scanf("%d%d%d", &n, &q, &s)){int tu, tv, tw;init(n+1);for(int i = 1; i < n; ++i){scanf("%d%d%d", &tu, &tv, &tw);insert(tu, tv, tw);insert(tv, tu, tw);rec[0][i] = tu;rec[1][i] = tv;rec[2][i] = tw;}lca.init();ft.init(n);for(int i = 1; i <= n; ++i){ft.add(poss[i], sumdist[i]);ft.add(poss[i]+1, -sumdist[i]);}int op1, op2, op3;for(int i = 0; i < q; ++i){scanf("%d", &op1);if(op1){scanf("%d%d", &op2, &op3);int ind = lca.dep[lca.pos[rec[0][op2]]] > lca.dep[lca.pos[rec[1][op2]]]? rec[0][op2]: rec[1][op2];int dif = op3-rec[2][op2];rec[2][op2] = op3;ft.add(poss[ind], dif);ft.add(pose[ind]+1, -dif);}else{scanf("%d", &op2);int ans = ft.query(poss[s])+ft.query(poss[op2])-2*ft.query(poss[lca.query(s, op2)]);s = op2;printf("%d\n", ans);}}}return 0;}