poj 3237 Tree 树链剖分

来源：互联网发布：淘宝网禁止出售的药品编辑：程序博客网时间：2024/05/16 07:06
对于区间取反的操作，记录区间最大值max_num,最小值min_num，这个区间取反就是max_num = -max_num;min_num = - min_num; swap(max_num,min_num)就可以，就可以传递lazy值了。

#include <map>#include <set>#include <queue>#include <cmath>#include <cstdio>#include <cstring>#include <cstdlib>#include <iostream>#include <algorithm>using namespace std;const int MAXN = 100010;struct Edge {    int to ;    int id;    int value;    Edge * next;}E[MAXN*2],*EE;struct Gragh {    Edge * first;}G[MAXN];struct Tree {    int x,y;    int max_num,min_num;    int lazy;}t[MAXN<<2];int pre[MAXN],son[MAXN],siz[MAXN],dep[MAXN],top[MAXN],pos[MAXN],Rank[MAXN];int N,Q,S;int num[MAXN];int idx[MAXN];int tree_idx = 0;int tot ;void Init() {    EE = E;    dep[1] = 1;    pre[1] = 0;    tree_idx = 0;    memset(G,0,sizeof(G));    memset(son,0,sizeof(son));}void addedge(int u,int v,int value,int id) {    EE->to = v ; EE->next = G[u].first ; EE->value = value ; EE->id = id ; G[u].first = EE++;    EE->to = u ; EE->next = G[v].first ; EE->value = value ; EE->id = id ; G[v].first = EE++;}void dfs1(int u) {    siz[u] = 1;    son[u] = 0;    for(Edge * p = G[u].first ; p ; p = p -> next) {        if(p->to != pre[u]) {            pre[p->to] = u;            dep[p->to] = dep[u] + 1;            dfs1(p->to);            siz[u] += siz[p->to];            if(siz[p->to] > siz[son[u]])                son[u] = p -> to;        }    }}void dfs2(int u,int ancestor) {    top[u] = ancestor;    tree_idx ++;    pos[u] = tree_idx;    if(son[u] != 0) {        dfs2(son[u],ancestor);    }    for(Edge * p = G[u].first ; p ; p = p -> next) {        if(p->to != pre[u] && p->to != son[u]) {            dfs2(p->to,p->to);            num[pos[p->to]] = p->value;            idx[p->id] = pos[p->to];        }        else if(p->to == son[u]) {            num[pos[p->to]] = p->value;            idx[p->id] = pos[p->to];        }    }} void Push_Up(int rt) {    t[rt].max_num = max(t[rt<<1].max_num,t[rt<<1|1].max_num);    t[rt].min_num = min(t[rt<<1].min_num,t[rt<<1|1].min_num);}void Push_Down(int rt) {    if(t[rt].lazy) {        t[rt<<1].lazy ^= 1;        t[rt<<1|1].lazy ^= 1;        t[rt<<1].max_num = -t[rt<<1].max_num;        t[rt<<1].min_num = -t[rt<<1].min_num;        swap(t[rt<<1].max_num,t[rt<<1].min_num);        t[rt<<1|1].max_num = -t[rt<<1|1].max_num;        t[rt<<1|1].min_num = -t[rt<<1|1].min_num;        swap(t[rt<<1|1].max_num,t[rt<<1|1].min_num);        t[rt].lazy = 0;    }}void Build(int x,int y,int rt) {    t[rt].x = x ; t[rt].y = y; t[rt].lazy = 0;     if(x == y) {        t[rt].max_num = num[x];        t[rt].min_num = num[x];        return ;    }    int mid = (x + y) >> 1;    Build(x,mid,rt<<1);    Build(mid+1,y,rt<<1|1);    Push_Up(rt);}void Update(int rt,int position,int value) {    if(t[rt].x == t[rt].y) {        t[rt].max_num = value;        t[rt].min_num = value;        return ;    }    int mid = (t[rt].x + t[rt].y) >> 1;    Push_Down(rt);    if(mid >= position) {        Update(rt<<1,position,value);    }    else {        Update(rt<<1|1,position,value);    }    Push_Up(rt);}void Ne_Update(int rt,int left,int right,int lazy) {    if(t[rt].x >= left && t[rt].y <= right) {        t[rt].lazy ^= 1;        t[rt].max_num = -t[rt].max_num;        t[rt].min_num = -t[rt].min_num;        swap(t[rt].max_num,t[rt].min_num);        return;    }    Push_Down(rt);    int mid = (t[rt].x + t[rt].y) >> 1;    if(mid >= left) {        Ne_Update(rt<<1,left,right,lazy);    }    if(mid < right) {        Ne_Update(rt<<1|1,left,right,lazy);    }    Push_Up(rt);}int ANS = 0;void Query(int rt,int left,int right) {    if(left <= t[rt].x && right >= t[rt].y) {        ANS = max(t[rt].max_num,ANS);        return ;    }    int ans = 0;    int mid = (t[rt].x + t[rt].y) >> 1;    Push_Down(rt);    if(mid >= left) {        Query(rt<<1,left,right);    }     if(mid < right){        Query(rt<<1|1,left,right);    }    Push_Up(rt);}void Change(int x,int y,int lazy) {    //printf("lazy : %d\n",lazy);    while(top[x] != top[y]) {        if(dep[top[x]] < dep[top[y]]) swap(x,y);        Ne_Update(1,pos[top[x]],pos[x],lazy);        x = pre[top[x]];    }    if(x == y) return ;    if(dep[x] > dep[y]) swap(x,y);    Ne_Update(1,pos[x]+1,pos[y],lazy);}void Query_Tree(int x,int y) {    int ans = 0;    while(top[x] != top[y]) {        if(dep[top[x]] < dep[top[y]]) swap(x,y);        Query(1,pos[top[x]],pos[x]);        x = pre[top[x]];    }    if(x == y) return ;    if(dep[x] > dep[y]) swap(x,y);    Query(1,pos[x]+1,pos[y]);}// void print_tree(int rt) {//     printf("x : %d y : %d lazy : %d\n",t[rt].x,t[rt].y,t[rt].lazy);//     if(t[rt].x == t[rt].y) {//         printf("%d ",t[rt].value);//         return ;//     }//     print_tree(rt<<1);//     print_tree(rt<<1|1);// }int ReadInt() {    char c = getchar();    while(c > '9' || c < '0') c = getchar();    int ret = 0;    while(c <= '9' && c >= '0') {        ret = ret * 10 + c - '0';        c = getchar();    }    return ret;}void input() {    int u,v,value;    for(int i = 1 ; i <= N - 1 ; i++) {        scanf("%d %d %d",&u,&v,&value);        addedge(u,v,value,i);    }    dfs1(1);    dfs2(1,1);    // for(int i = 1 ; i <= N ; i++) {    //     Rank[pos[i]] = num[i];    // }    Build(1,N,1);    char op[10];    int x,y;    while(scanf("%s",op)) {        if(op[0] == 'D') break;        scanf("%d %d",&x,&y);        if(op[0] == 'C') {            Update(1,idx[x],y);        }        else if(op[0] == 'N') {            Change(x,y,1);        }        else {            ANS = -2147483648;            Query_Tree(x,y);            printf("%d\n",ANS);        }    }}int main(void) {    freopen("a.in","r",stdin);    int T;    scanf("%d",&T);    while(T--) {        scanf("%d",&N);        Init();        input();        //solve();    }    return 0;}
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