zoj 2112 （主席树）

Orz......

#include <bits/stdc++.h>using namespace std;const int MAXN = 60010;const int MAXQ = 10010;const int MAXM = 2500010;int n, m, dex;int a[MAXN], sorted[MAXN], root[MAXN], lower[MAXN], temp[MAXN];int T[MAXM], lson[MAXM], rson[MAXM];struct Query {int kind, a, b, c;}query[MAXQ];int BuildT(int l, int r) {int now = ++dex;T[now] = 0;if(l == r) return now;int mid = (l + r) >> 1;lson[now] = BuildT(l, mid);rson[now] = BuildT(mid + 1, r);return now;}int UpdateT(int oldroot, int pos, int val) {int now = ++dex;int tmp = now;T[now] = T[oldroot] + val;int l = 1, r = m;while(l < r) {int mid = (l + r) >> 1;if(pos <= mid) {rson[now] = rson[oldroot];lson[now] = ++dex;T[lson[now]] = T[lson[oldroot]] + val;now = lson[now], oldroot = lson[oldroot];r = mid;}else {lson[now] = lson[oldroot];rson[now] = ++dex;T[rson[now]] = T[rson[oldroot]] + val;now = rson[now], oldroot = rson[oldroot];l = mid + 1;}}T[now] = T[oldroot] + val;return tmp;}int lowerbit(int x) {return x & (-x);}int getsum(int x) {int ans = 0;while(x) {ans += T[lson[temp[x]]];x -= lowerbit(x);}return ans;}int QueryT(int l, int r, int k) {int rootl = root[l];int rootr = root[r];int left = 1, right = m;for(int i = r; i; i -= lowerbit(i)) temp[i] = lower[i];for(int i = l; i; i -= lowerbit(i)) temp[i] = lower[i];while(left < right) {int con = T[lson[rootr]] - T[lson[rootl]] + getsum(r) - getsum(l);int mid = (left + right) >> 1;if(k <= con) {for(int i = r; i; i -= lowerbit(i)) temp[i] = lson[temp[i]];for(int i = l; i; i -= lowerbit(i)) temp[i] = lson[temp[i]];rootl = lson[rootl], rootr = lson[rootr];right = mid;}else {k -= con;for(int i = r; i; i -= lowerbit(i)) temp[i] = rson[temp[i]];for(int i = l; i; i -= lowerbit(i)) temp[i] = rson[temp[i]];rootl = rson[rootl], rootr = rson[rootr];left = mid + 1;}}return left;}void UpdateL(int x, int pos, int val) {while(x <= n) {lower[x] = UpdateT(lower[x], pos, val);x += lowerbit(x);}}int main() {int t;scanf("%d", &t);while(t--) {int q;dex = m = 0;scanf("%d%d", &n, &q);for(int i = 1; i <= n; i++) scanf("%d", &a[i]), sorted[++m] = a[i];char op[2];for(int i = 1; i <= q; i++) {scanf("%s", op);if(op[0] == 'Q') scanf("%d%d%d", &query[i].a, &query[i].b, &query[i].c), query[i].kind = 1;else scanf("%d%d", &query[i].a, &query[i].b), query[i].kind = 2, sorted[++m] = query[i].b;}sort(sorted + 1, sorted + 1 + m);m = unique(sorted + 1, sorted + 1 + m) - sorted - 1;root[0] = BuildT(1, m);for(int i = 1; i <= n; i++) {int pos = lower_bound(sorted + 1, sorted + 1 + m, a[i]) - sorted;root[i] = UpdateT(root[i - 1], pos, 1);}for(int i = 1; i <= n; i++) lower[i] = root[0];for(int i = 1; i <= q; i++) {if(query[i].kind == 1) printf("%d\n", sorted[QueryT(query[i].a - 1, query[i].b, query[i].c)]);else {int pos = lower_bound(sorted + 1, sorted + 1 + m, a[query[i].a]) - sorted;UpdateL(query[i].a, pos, -1);pos = lower_bound(sorted + 1, sorted + 1 + m, query[i].b) - sorted;UpdateL(query[i].a, pos, 1);a[query[i].a] = query[i].b;}}}return 0;}