如题，这是一个模板。。。
#include <algorithm> #include <iostream> #include <cstring> #include <cstdio> #include <cctype> #define max(x, y) (x > y ? x : y) #define min(x, y) (x < y ? x : y) inline void read(int & x) { x = 0; int k = 1; char c = getchar(); while (!isdigit(c)) if (c == '-') c = getchar(), k = -1; else c = getchar(); while (isdigit(c)) x = (x << 1) + (x << 3) + (c ^ 48), c = getchar(); x *= k; } const int inf = 2147483647; const int N = 4001000; int n, m, tot, l, r, x, y, z, opt, mxa = -2147483647; int cnt[N], faz[N], val[N], siz[N], a[N], son[N][2], root[N]; //======================================================================= //Splay inline int Getson(int u) { return son[faz[u]][1] == u; } inline void Pushup(int u) { siz[u] = siz[son[u][0]] + siz[son[u][1]] + cnt[u]; } inline int Getmin(int u) { while (son[u][0]) u = son[u][0]; return u; } inline int Getmax(int u) { while (son[u][1]) u = son[u][1]; return u; } inline int Getx(int rtid, int x) { int u = root[rtid], las = 0; while (u && val[las = u] != x) if (x >= val[u]) u = son[u][1]; else u = son[u][0]; return u ? u : las; } void Rotate(int u) { int y = faz[u], z = faz[y], ch = Getson(u); int b = son[u][ch ^ 1], d = Getson(y); son[u][ch ^ 1] = y, son[y][ch] = b; faz[y] = u, faz[b] = y, faz[u] = z; if (z) son[z][d] = u; Pushup(y), Pushup(u); } void Splay(int rtid, int u, int tar) { while (faz[u] != tar) { if (faz[faz[u]] != tar) if (Getson(u) == Getson(faz[u])) Rotate(faz[u]); else Rotate(u); Rotate(u); } if (!tar) root[rtid] = u; } inline void Insert(int rtid, int x) { int u = root[rtid], las = 0; if (!root[rtid]) { root[rtid] = u = ++tot; val[u] = x; siz[u] = cnt[u] = 1; faz[u] = son[u][0] = son[u][1] = 0; return; } while (true) { ++siz[u]; if (x == val[u]) { ++cnt[u]; break; } las = u; if (x > val[u]) u = son[u][1]; else u = son[u][0]; if (!u) { u = ++tot, val[u] = x, faz[u] = las, son[las][x > val[las]] = u; son[u][0] = son[u][1] = 0, siz[u] = cnt[u] = 1; break; } } Splay(rtid, u, 0); } inline void Delete(int rtid, int x) { int u = root[rtid]; while (u) if (x == val[u]) { Splay(rtid, u, 0); if (cnt[u] > 1) { --cnt[u], --siz[u]; return; } if (!son[u][0] || !son[u][1]) { root[rtid] = son[u][0] | son[u][1]; faz[root[rtid]] = 0; return; } int newrt = Getmin(son[u][1]); faz[son[u][1]] = 0, faz[son[u][0]] = newrt, son[newrt][0] = son[u][0]; Splay(rtid, newrt, 0); return; } else if (x > val[u]) u = son[u][1]; else u = son[u][0]; } inline int Getkth(int rtid, int k) { int u = root[rtid]; if (siz[u] < k) return -inf; while (u) if (siz[son[u][0]] >= k) u = son[u][0]; else if (siz[son[u][0]] + cnt[u] < k) k -= siz[son[u][0]] + cnt[u], u = son[u][1]; else return val[u]; } inline int Getrank(int rtid, int x) { //-------------------·½·¨Ò»------------------------ //Wrong Answer /* int u = Getx(rtid, x); Splay(rtid, u, 0); return siz[son[u][0]]; */ //-------------------·½·¨¶þ------------------------ int sum = 0, u = root[rtid]; while (u) if (x == val[u]) return sum + siz[son[u][0]]; else if (x > val[u]) sum += siz[son[u][0]] + cnt[u], u = son[u][1]; else u = son[u][0]; return sum; } int Pre(int rtid, int x) { int u = Getx(rtid, x); if (val[u] < x) return val[u]; Splay(rtid, u, 0); return son[u][0] == 0 ? -inf : val[Getmax(son[u][0])]; } int Suf(int rtid, int x) { int u = Getx(rtid, x); if (val[u] > x) return val[u]; Splay(rtid, u, 0); return son[u][1] == 0 ? inf : val[Getmin(son[u][1])]; } //Splay End //======================================================================= //Segment tree Begin #define Root 1, 1, n #define Lson u << 1, l, mid #define Rson u << 1 | 1, mid + 1, r #define ls (u << 1) #define rs (u << 1 | 1) #define mid (l + r >> 1) #define MID (L + R >> 1) inline void Segins(int u, int l, int r, int p, int x) { Insert(u, x); if (l == r) return; if (p <= mid) Segins(Lson, p, x); else Segins(Rson, p, x); } inline void Segmdf(int u, int l, int r, int p, int x) { Delete(u, a[p]), Insert(u, x); if (l == r) { a[p] = x; return; } if (p <= mid) Segmdf(Lson, p, x); else Segmdf(Rson, p, x); } inline int Segrak(int u, int l, int r, int x, int y, int z) { if (l == x && r == y) return Getrank(u, z); if (y <= mid) return Segrak(Lson, x, y, z); if (x > mid) return Segrak(Rson, x, y, z); return Segrak(Lson, x, mid, z) + Segrak(Rson, mid + 1, y, z); } inline int Segpre(int u, int l, int r, int x, int y, int z) { if (l == x && r == y) return Pre(u, z); if (y <= mid) return Segpre(Lson, x, y, z); if (x > mid) return Segpre(Rson, x, y, z); return max(Segpre(Lson, x, mid, z), Segpre(Rson, mid + 1, y, z)); } inline int Segsuf(int u, int l, int r, int x, int y, int z) { if (l == x && r == y) return Suf(u, z); if (y <= mid) return Segsuf(Lson, x, y, z); if (x > mid) return Segsuf(Rson, x, y, z); return min(Segsuf(Lson, x, mid, z), Segsuf(Rson, mid + 1, y, z)); } inline int Segkth(int l, int r, int k) { int cur, L = 0, R = mxa + 1; while (L < R) { cur = Segrak(Root, l, r, MID); if (cur < k) L = MID + 1; else R = MID; } return L - 1; } signed main() { read(n), read(m); for (int i = 1; i <= n; ++i) { read(a[i]); Segins(Root, i, a[i]); mxa = max(mxa, a[i]); } for (int i = 1; i <= m; ++i) { read(opt); if (opt == 3) read(x), read(y), Segmdf(Root, x, y); else { read(l), read(r), read(x); if (opt == 1) printf("%d\n", Segrak(Root, l, r, x) + 1); if (opt == 2) printf("%d\n", Segkth(l, r, x)); if (opt == 4) printf("%d\n", Segpre(Root, l, r, x)); if (opt == 5) printf("%d\n", Segsuf(Root, l, r, x)); } } return 0; }