zoj 2112 Dynamic Rankings/树套树

原题链接：http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemId=1112

简单的线段树套平衡树，开始时内存池开小了没发现，满屏的sf(Segmentation Fault)/(ㄒoㄒ)/~~

其实树套树很好理解，就是线段树每个节点套个平衡树，求区间k大的时候直接二分即可。

当修改序列某个元素时，直接将其删除，再插入新的元素。。。

具体如下：

#include<cstdio>#include<cstdlib>#include<cstring>#include<algorithm>#define lc root<<1#define rc root<<1|1#define INF 0x3f3f3f3fconst int Max_N = 50010;struct SBT{int key, size, cnt;SBT *ch[2];inline void push_up(){size = ch[0]->size + ch[1]->size + cnt;}int cmp(int v) const{if (v == key) return -1;return v > key;}}*null, stack[Max_N * 18], *ptr[Max_N << 2];int sz = 0, sum = 0, arr[Max_N];void init(){null = &stack[sz++];null->key = null->size = null->cnt = 0;}void rotate(SBT* &x, int d){SBT *k = x->ch[!d];x->ch[!d] = k->ch[d];k->ch[d] = x;k->size = x->size;x->push_up();x = k;}void Maintain(SBT* &x, int d){if (x->ch[d] == null) return;if (x->ch[d]->ch[d]->size > x->ch[!d]->size){rotate(x, !d);} else if (x->ch[d]->ch[!d]->size > x->ch[!d]->size){rotate(x->ch[d], d), rotate(x, !d);} else {return;}Maintain(x, 0), Maintain(x, 1);}void insert(SBT* &x, int key){if (x == null){x = &stack[sz++];x->ch[0] = x->ch[1] = null;x->key = key, x->size = x->cnt = 1;} else {int d = x->cmp(key);x->size++;if (-1 == d){x->cnt++;return;}insert(x->ch[d], key);x->push_up();Maintain(x, d);}}void del(SBT* &x, int key){if (x == null) return;int d = x->cmp(key);x->size--;if (-1 == d){if (x->cnt > 1){x->cnt--;} else if (x->ch[0] == null || x->ch[1] == null){x = x->ch[0] != null ? x->ch[0] : x->ch[1];} else {SBT *ret = x->ch[1];for (; ret->ch[0] != null; ret = ret->ch[0]);del(x->ch[1], x->key = ret->key);}} else {del(x->ch[d], key);}if (x != null) x->push_up();}int sbt_rank(SBT *x, int key){int t, cur;for (t = cur = 0; x != null;){t = x->ch[0]->size;if (key < x->key) x = x->ch[0];else if (key >= x->key) cur += x->cnt + t, x = x->ch[1];}return cur;}void seg_built(int root, int l, int r){for (int i = l; i <= r; i++) insert(ptr[root], arr[i]);if (l == r) return;int mid = (l + r) >> 1;seg_built(lc, l, mid);seg_built(rc, mid + 1, r);}void seg_query(int root, int l, int r, int x, int y, int val){if (x > r || y < l) return;if (x <= l && y >= r){sum += sbt_rank(ptr[root], val);return;}int mid = (l + r) >> 1;seg_query(lc, l, mid, x, y, val);seg_query(rc, mid + 1, r, x, y, val);}void seg_del(int root, int l, int r, int pos, int val){if (pos > r || pos < l) return;del(ptr[root], val);if (l == r) return;int mid = (l + r) >> 1;seg_del(lc, l, mid, pos, val);seg_del(rc, mid + 1, r, pos, val);}void seg_insert(int root, int l, int r, int pos, int val) {if (pos > r || pos < l) return;insert(ptr[root], val);if (l == r) return;int mid = (l + r) >> 1;seg_insert(lc, l, mid, pos, val);seg_insert(rc, mid + 1, r, pos, val);}void gogo(int n, int a, int b, int k){int l = 0, r = INF;while (l < r){sum = 0;int mid = (l + r) >> 1;seg_query(1, 1, n, a, b, mid);if (sum < k) l = mid + 1;else r = mid;}printf("%d\n", l);}int main(){#ifdef LOCALfreopen("in.txt", "r", stdin);freopen("out.txt", "w+", stdout);#endifchar ch;int t, n, m, a, b, k;scanf("%d", &t);while (t--){sz = 0, init();scanf("%d %d", &n, &m);for (int i = 1; i <= n; i++) scanf("%d", &arr[i]);std::fill(ptr, ptr + (n << 2), null);seg_built(1, 1, n);while (m--){getchar();scanf("%c", &ch);if (ch == 'Q'){scanf("%d %d %d", &a, &b, &k);gogo(n, a, b, k);}else {scanf("%d %d", &a, &b);seg_del(1, 1, n, a, arr[a]);seg_insert(1, 1, n, a, arr[a] = b);}}}return 0;}