BZOJ 1503 郁闷的出纳员

平衡树

这题感觉用splay会更好写，我们用平衡树维护相对工资。
用一个变量记录工资增减的变化，也就是说存进树的值是x-w，每次工资减少后，假设记录工资变化的变量为m，直接把m-w的前驱splay到根，删除左子树即可

#include <bits/stdc++.h>
#define INF 0x3f3f3f3f
#define full(a, b) memset(a, b, sizeof a)
using namespace std;
typedef long long ll;
inline int lowbit(int x){ return x & (-x); }
inline int read(){
    int X = 0, w = 0; char ch = 0;
    while(!isdigit(ch)) { w |= ch == '-'; ch = getchar(); }
    while(isdigit(ch)) X = (X << 3) + (X << 1) + (ch ^ 48), ch = getchar();
    return w ? -X : X;
}
inline int gcd(int a, int b){ return a % b ? gcd(b, a % b) : b; }
inline int lcm(int a, int b){ return a / gcd(a, b) * b; }
template<typename T>
inline T max(T x, T y, T z){ return max(max(x, y), z); }
template<typename T>
inline T min(T x, T y, T z){ return min(min(x, y), z); }
template<typename A, typename B, typename C>
inline A fpow(A x, B p, C lyd){
    A ans = 1;
    for(; p; p >>= 1, x = 1LL * x * x % lyd)if(p & 1)ans = 1LL * x * ans % lyd;
    return ans;
}
const int N = 1000005;
int n, m, t;
struct Node{
    int val, size, num;
    Node *son[2], *fa;
}*root, *null, *NI, a[N];

Node *newNode(Node *fa, int val){
    Node *node = &a[t++];
    node->val = val, node->size = 1, node->num = 1, node->fa = fa;
    node->son[0] = node->son[1] = null;
    return node;
}

void push_up(Node *node){
    if(node == NI) return;
    node->size = node->son[0]->size + node->son[1]->size + node->num;
}

void rotate(Node *x, int p){
    Node *y = x->fa;
    y->son[p^1] = x->son[p];
    if(x->son[p] != null) x->son[p]->fa = y;
    y->fa->son[y->fa->son[1] == y] = x;
    x->fa = y->fa;
    x->son[p] = y;
    y->fa = x;
    push_up(y), push_up(x);
}

void splay(Node *node, Node *goal){
    if(node == goal) return;
    while(node->fa != goal){
        Node *fa = node->fa, *gfa = fa->fa;
        if(gfa == goal){
            rotate(node, fa->son[0] == node);
            break;
        }
        int p = gfa->son[1] == fa;
        if((fa->son[1] == node) == p){
            rotate(fa, p^1);
            rotate(node, p^1);
        }
        else{
            rotate(node, p);
            rotate(node, p^1);
        }
    }
    push_up(node);
    if(goal == NI) root = node;
}

void insert(int x){
    if(root == null || root == NULL){
        root = newNode(NI, x);
        return;
    }
    Node *node = root;
    while(node->son[x > node->val] != null){
        if(node->val == x) break;
        node = node->son[x > node->val];
    }
    if(node->val == x){
        node->size ++, node->num ++;
        splay(node, NI);
        return;
    }
    node->son[x > node->val] = newNode(node, x);
    splay(node->son[x > node->val], NI);
}

void find(int x){
    Node *node = root;
    while(x != node->val && node->son[x > node->val] != null)
        node = node->son[x > node->val];
    splay(node, NI);
}

Node *successor(int x){
    find(x);
    if(root->val >= x) return root;
    Node *node = root->son[1];
    while(node->son[0] != null) node = node->son[0];
    return node;
}

int del(int x){
    int ret = 0;
    Node *node = successor(x);
    splay(node, NI);
    ret += root->son[0]->size;
    root->son[0] = null;
    push_up(root);
    return ret;
}

int select(int k){
    Node *node = root;
    int m = node->son[0]->size;
    while(!(k > m && k <= m + node->num)){
        if(k > m){
            k -= m + node->num;
            node = node->son[1];
        }
        else node = node->son[0];
        m = node->son[0]->size;
    }
    splay(node, NI);
    return node->val;
}
// x + w >= m
// x >= m - w
int main(){

    n = read(), m = read();
    int w = 0, lf = 0, cnt = 0;
    null = &a[t++], NI = &a[t++];
    insert(INF), root->size = root->num = 0;
    while(n --){
        char opt[2]; scanf("%s", opt);
        if(opt[0] == 'I'){
            int x = read();
            if(x >= m) insert(x - w), cnt ++;
        }
        else if(opt[0] == 'A') w += read();
        else if(opt[0] == 'S'){
            w -= read();
            int tmp = del(m - w);
            cnt -= tmp, lf += tmp;
        }
        else{
            int k = read();
            if(k > cnt) printf("-1\n");
            else printf("%d\n", select(cnt - k + 1) + w);
        }
    }
    printf("%d\n", lf);
    return 0;
}