树链剖分学习记录
HDU 3966
基于点权 改动（增减）一条路径上的点 单结点查询
code：
#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int maxn = 50010;
struct Edge{
int to, next;
}edge[maxn*2];
int head[maxn], tot;
int top[maxn];
int fa[maxn];
int deep[maxn];
int num[maxn];
int p[maxn];
int fp[maxn];
int son[maxn];
int pos;
void init(){
tot = 0;
memset(head, -1, sizeof(head));
pos = 1;
memset(son, -1, sizeof(son));
}
void add_Edge(int u, int v){
edge[tot].to = v;
edge[tot].next = head[u];
head[u] = tot++;
}
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].to;
if(v == pre) continue;
dfs1(v, u, d+1);
num[u] += num[v];
if(son[u] == -1 || num[v] > num[son[u]]) 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].to;
if(v == son[u]) continue;
if(v == fa[u]) continue;
getpos(v, v);
}
}
int n;
int a[maxn];
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
int sum[maxn<<2],col[maxn<<2];
void pushdown(int rt, int m)
{
if(col[rt])
{
col[rt<<1] += col[rt];
col[rt<<1|1] += col[rt];
sum[rt<<1] += (m-(m>>1))*col[rt];
sum[rt<<1|1] += (m>>1)*col[rt];
col[rt] = 0;
}
}
void build(int l,int r,int rt)
{
col[rt]=0;
if(l==r)
{
sum[rt] = a[fp[l]];
return;
}
int m=(l+r)>>1;
build(lson);
build(rson);
}
void update(int L,int R,int c,int l,int r,int rt)
{
if(L<=l&&R>=r)
{
col[rt] += c;
sum[rt] += c*(r-l+1);
return;
}
pushdown(rt,r-l+1);
int m=(l+r)>>1;
if(L<=m)
update(L,R,c,lson);
if(R>m)
update(L,R,c,rson);
}
int query(int p, int l, int r, int rt){
if(l == r) return sum[rt];
pushdown(rt, r-l+1);
int m = (l + r) >> 1;
if(p <= m) return query(p, lson);
else return query(p, rson);
}
void change(int u, int v, int val){
int f1 = top[u], f2 = top[v];
while(f1 != f2){
if(deep[f1] < deep[f2]){
swap(f1, f2);
swap(u, v);
}
update(p[f1], p[u], val, 1, n, 1);
u = fa[f1];
f1 = top[u];
}
if(deep[u] > deep[v]) swap(u, v);
update(p[u], p[v], val, 1, n, 1);
}
int main(){
int M, P;
while(scanf("%d%d%d",&n, &M, &P) != EOF){
init();
for(int i = 1; i <= n; i++) scanf("%d",&a[i]);
int u, v;
while(M--){
scanf("%d%d",&u, &v);
add_Edge(u, v);
add_Edge(v, u);
}
dfs1(1, 0, 0);
getpos(1, 1);
build(1, n, 1);
char op[10];
int x, y, z;
while(P--){
scanf("%s", op);
if(op[0] == 'I'){
scanf("%d%d%d",&x, &y, &z);
change(x, y, z);
}
else if(op[0] == 'D'){
scanf("%d%d%d",&x, &y, &z);
change(x, y, -z);
}
else{
scanf("%d",&x);
printf("%d\n",query(p[x], 1, n, 1));
}
}
}
return 0;
}
SPOJ QTREE（树链剖分）
基于边权 改动单条边权 查询路径边权最大值
code：
#include<cstdio>
#include<cstring>
#include<algorithm>
#define INF 0x3f3f3f3f
using namespace std;
const int maxn = 10010;
struct Edge{
int to, next;
}edge[maxn*2];
int head[maxn], tot;
int top[maxn];
int fa[maxn];
int deep[maxn];
int num[maxn];
int p[maxn];
int fp[maxn];
int son[maxn];
int pos;
void init(){
tot = 0;
memset(head, -1, sizeof(head));
pos = 1;
memset(son, -1, sizeof(son));
}
void add_Edge(int u, int v){
edge[tot].to = v;
edge[tot].next = head[u];
head[u] = tot++;
}
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].to;
if(v != pre){
dfs1(v, u, d+1);
num[u] += num[v];
if(son[u] == -1 || num[v] > num[son[u]]){
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].to;
if(v != fa[u] && v != son[u]){
getpos(v, v);
}
}
}
#define lson l, m, rt<<1
#define rson m+1, r, rt<<1|1
int n;
int sum[maxn<<4];
void pushup(int rt){
sum[rt] = max(sum[rt<<1], sum[rt<<1|1]);
}
void build(int l, int r, int rt){
sum[rt] = 0;
if(l == r) return;
int m = (l + r) >> 1;
build(lson);
build(rson);
pushup(rt);
}
void update(int pp, int vv, int l, int r, int rt){
if(l == r){
sum[rt] = vv;
return;
}
int m = (l + r) >> 1;
if(pp <= m) update(pp, vv, lson);
else update(pp, vv, rson);
pushup(rt);
}
int query(int L, int R, int l, int r, int rt){
if(L <= l && R >= r){
return sum[rt];
}
int m = (l + r) >> 1;
int ret = -INF;
if(L <= m) ret = max(ret, query(L, R, lson));
if(R > m) ret = max(ret, query(L, R, rson));
return ret;
}
int find_(int u, int v){
int f1 = top[u], f2 = top[v];
int tmp = -INF;
while(f1 != f2){
// printf("!\n");
if(deep[f1] < deep[f2]){
swap(f1, f2);
swap(u, v);
}
tmp = max(tmp, query(p[f1], p[u], 1, n, 1));
u = fa[f1]; f1 = top[u];
}
if(u == v){
return tmp;
}
if(deep[u] > deep[v]){
swap(u, v);
}
// printf("* %d %d *\n", u, v);
// printf("* %d %d *\n", p[son[u]], p[v]);
tmp = max(tmp, query(p[son[u]], p[v], 1, n, 1));
return tmp;
}
int e[maxn][3];
int main(){
int t;
scanf("%d",&t);
while(t--){
init();
scanf("%d", &n);
int u, v, w;
for(int i = 1; i < n; i++){
scanf("%d%d%d", &u, &v, &w);
e[i][0] = u;
e[i][1] = v;
e[i][2] = w;
add_Edge(u, v);
add_Edge(v, u);
}
dfs1(1, 0, 0);
getpos(1, 1);
build(1, n, 1);
// for(int i = 1; i <= n; i++){
// printf("i = %d pos = %d\n", i, top[i]);
// }
for(int i = 1; i < n; i++){
u = e[i][0];
v = e[i][1];
if(deep[u] < deep[v]){
swap(u, v);
swap(e[i][0], e[i][1]);
}
// printf("== %d %d ==\n", p[u], p[v]);
update(p[u], e[i][2], 1, n, 1);
// printf("bian = %d\n", query(p[u], p[u], 1, n, 1));
}
char op[20];
int x, y;
while(scanf("%s", op)){
if(op[0] == 'D') break;
scanf("%d%d",&x, &y);
if(op[0] == 'C'){
// printf("kao = %d\n", p[e[x][0]]);
update(p[e[x][0]], y, 1, n, 1);
}
else{
printf("%d\n", find_(x, y));
}
}
}
return 0;
}
/*
1
3
1 2 1
2 3 2
QUERY 1 2
CHANGE 1 3
QUERY 1 2
DONE
*/
