HDU 3966 (tree link splitting + vertex modification + vertex query)

Question link:Http://acm.hdu.edu.cn/showproblem.php? PID = 1, 3966

Theme: The camp is distributed in a tree. Each camp has some people. Each time you modify the number of people in all the camps on a chain, you can query a single point each time.

Solutions:

Tree link splitting basic questions.

Maintain a sum.

Note that when modifying the light chain, click Modify and edge modify are different.

Because the tree structure is not the same as the sequence of the Line Segment tree points, a rank ing array rank is required. Therefore, when building the online segment tree, the weight is Camp [rank [l]. The rank ing of rank in this step is completed at dfs2, where rank [W [u] = u;

When querying a single point U, W [u] is the position in its online segment tree.

# pragma comment (linker, "/Stack: 1024000000,1024000000") # include "cstdio" # include "vector" # include "cstring" using namespace STD; # define maxn 50005int camp [maxn], s [maxn], DEP [maxn], POS [maxn], son [maxn], top [maxn], Fa [maxn], W [maxn], rank [maxn], CNT, N; vector G [maxn]; void dfs1 (int u, int pre, int D) {s [u] = 1; Fa [u] = pre; Dep [u] = D; For (INT I = 0; I S [son [u]) Son [u] = V ;}} void dfs2 (int u, int TP) {W [u] = ++ CNT; top [u] = TP; rank [W [u] = u; If (son [u] =-1) return; dfs2 (son [u], TP); For (INT I = 0; I 1; build (lson); Build (rson); pushup (Root);} void Pushdown (INT root, int m) {If (COL [root]) {Col [root <1] + = Col [Ro Ot]; Col [root <1 | 1] + = Col [root]; sum [root <1] + = (m-(M> 1 )) * Col [root]; sum [root <1 | 1] + = (M> 1) * Col [root]; Col [root] = 0 ;}} void Update (int l, int R, int V, int L, int R, int root) {If (L <= L & R <= r) {Col [root] + = V; sum [root] + = (R-l + 1) * V; return;} Pushdown (root, R-l + 1 ); int mid = (L + r)> 1; if (L <= mid) Update (L, R, V, lson); If (r> mid) Update (L, r, V, rson); pushup (Root);} int query (int p, int L, int R, int root) {If (L = r) retu Rn sum [root]; Pushdown (root, R-l + 1); int mid = (L + r)> 1, ret = 0; If (P <= mid) ret = query (p, lson); else ret = query (p, rson); return ret;} void change (int x, int y, int V) {While (top [x]! = Top [y]) {If (DEP [top [x] Dep [y]) Swap (x, y); Update (W [X], W [Y], V, 1, n, 1 ); // different from edge modification} int main () {// freopen ("in.txt", "r", stdin); int M, P, U, V, C; while (scanf ("% d", & N, & M, & P )! = EOF) {memset (son,-1, sizeof (son); For (INT I = 0; I <= N; I ++) g [I]. clear (); CNT = 0; For (INT I = 1; I <= N; I ++) scanf ("% d", & Camp [I]); for (INT I = 1; I <= m; I ++) {scanf ("% d", & U, & V); G [u]. push_back (V); G [v]. push_back (U);} dfs1 (1, 1); dfs2 (1, 1); Build (1, n, 1); char cmd [10]; for (INT I = 1; I <= P; I ++) {scanf ("% s", & cmd); If (CMD [0] = 'I ') {scanf ("% d", & U, & V, & C); change (u, v, c );} if (CMD [0] = 'D') {scanf ("% d", & U, & V, & C); change (u, v, -C);} If (CMD [0] = 'q') {scanf ("% d", & C); printf ("% d \ n ", query (W [c], 1, n, 1) ;}}}

11757337

16:51:29

Accepted

3966

2484 Ms

8308 K

3299 B

C ++

Physcal

HDU 3966 (tree link splitting + vertex modification + vertex query)