HDU 1540

来源：互联网发布：淘宝哪里有信用卡编辑：程序博客网时间：2024/05/21 11:39

void pushup(int pos){    node[pos].lx = node[lson].lx;    node[pos].rx = node[rson].rx;    if(node[pos].lx == node[lson].len()) node[pos].lx += node[rson].lx;    if(node[pos].rx == node[rson].len()) node[pos].rx += node[lson].rx;    node[pos].mx = node[lson].rx + node[rson].lx;    node[pos].mx = max(node[pos].mx,max(node[lson].mx,node[rson].mx));}

/*Tunnel Warfare经典题：区间合并求某点所在区间的最大长度*/#include<cstdio>#include<cmath>#include<cstring>#include<vector>#include<stack>#include<algorithm>using namespace std;typedef long long LL;#define lson (pos<<1)#define rson (pos<<1|1)const int maxn = 55555;int n,m,x;char op[10];struct Node{   int l,r,lx,rx,mx;   int mid(){        return (l + r) >> 1;   }   int len(){        return (r - l + 1);   }}node[maxn << 2];void pushup(int pos){    node[pos].lx = node[lson].lx;    node[pos].rx = node[rson].rx;    if(node[pos].lx == node[lson].len()) node[pos].lx += node[rson].lx;    if(node[pos].rx == node[rson].len()) node[pos].rx += node[lson].rx;    node[pos].mx = node[lson].rx + node[rson].lx;    node[pos].mx = max(node[pos].mx,max(node[lson].mx,node[rson].mx));}void build(int l,int r,int pos){    node[pos].l = l;    node[pos].r = r;    if(l == r){        node[pos].lx = node[pos].rx = node[pos].mx = 1;        return;    }    int mid = node[pos].mid();    build(l,mid,lson);    build(mid + 1,r,rson);    pushup(pos);}void update(int pos,int m,int d){    if(node[pos].l == node[pos].r){        node[pos].lx = node[pos].rx = node[pos].mx = d;        return;    }    int mid = node[pos].mid();    if(m <= mid)        update(lson,m,d);    else        update(rson,m,d);    pushup(pos);}int query(int pos,int m){    if(node[pos].l == node[pos].r || node[pos].mx == 0 || node[pos].mx == node[pos].len()){        return node[pos].mx;    }    int mid = node[pos].mid();    if(m <= mid){        int v = mid - node[lson].rx + 1;        if(m >= v)            return query(lson,m) + query(rson,mid + 1);        else            return query(lson,m);    }    if(m > mid){        int v = mid + node[rson].lx;        if(m  <=  v)            return query(rson,m) + query(lson,mid);        else            return query(rson,m);    }}void debug(int pos){    printf("[%d %d] lx:%d rx:%d mx:%d\n",node[pos].l,node[pos].r,node[pos].lx,node[pos].rx,node[pos].mx);    if(node[pos].l == node[pos].r) return;    debug(lson);    debug(rson);}int main(){    while(scanf("%d%d",&n,&m) != EOF){        build(1,n,1);        stack<int>st;        for(int i = 0; i < m; i++){            scanf("%s",op);            if(op[0] == 'D'){                scanf("%d",&x);                st.push(x);                update(1,x,0);            }            else if(op[0] == 'R'){                if(st.empty()) continue;                x = st.top();                st.pop();                update(1,x,1);            }            else if(op[0] == 'Q'){                scanf("%d",&x);                printf("%d\n",query(1,x));            }        }    }    return 0;}

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