HDU 1540 POJ 2892 Tunnel Warfare

线段树 区间合并 单点修改 区间查询。又是1秒钟构思，差错查了好久... ... 发现一个int型的定义成了char型，打脸。

#include <stdio.h>
#include <string.h>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <string>
#include <math.h>
#include <stdlib.h>
#include <time.h>
using namespace std;

const int maxn= +;
int N,Q;
char op[];
int num;
stack<int>S;
bool flag[maxn];
struct SegTree
{
    int lsum,rsum,msum;
}segTree[*maxn];
int fail,ans1,ans2;

void pushUp(int rt,int len)
{
    if(segTree[*rt].lsum==len-len/)
        segTree[rt].lsum=segTree[*rt].lsum+segTree[*rt+].lsum;
    else segTree[rt].lsum=segTree[*rt].lsum;

    if(segTree[*rt+].rsum==len/)
        segTree[rt].rsum=segTree[*rt].rsum+segTree[*rt+].rsum;
    else segTree[rt].rsum=segTree[*rt+].rsum;

    segTree[rt].msum=max(segTree[*rt].msum,segTree[*rt+].msum);
    segTree[rt].msum=max(segTree[rt].msum,segTree[*rt+].lsum+segTree[*rt].rsum);
}

void build(int l,int r,int rt)
{
    if(l==r)
    {
        segTree[rt].lsum=segTree[rt].rsum=segTree[rt].msum=;
        return;
    }

    int m=(l+r)/;
    build(l,m,*rt);
    build(m+,r,*rt+);
    pushUp(rt,r-l+);
}

void update(int info,int node,int l,int r,int rt)
{
    if(l==r&&node==l)
    {
        segTree[rt].lsum=segTree[rt].rsum=segTree[rt].msum=info;
        return;
    }

    int m=(l+r)/;
    if(node<=m) update(info,node,l,m,*rt);
    else update(info,node,m+,r,*rt+);

    pushUp(rt,r-l+);
}

void quary1(int L,int R,int l,int r,int rt)
{
    if(L<=l&&r<=R)
    {
        ans1=ans1+segTree[rt].rsum;
        if(segTree[rt].rsum!=r-l+) fail=;
        return;
    }

    int m=(l+r)/;
    if(R>m) quary1(L,R,m+,r,*rt+);
    if(fail) return;
    if(L<=m) quary1(L,R,l,m,*rt);
    if(fail) return;
}

void quary2(int L,int R,int l,int r,int rt)
{
    if(L<=l&&r<=R)
    {
        ans2=ans2+segTree[rt].lsum;
        if(segTree[rt].lsum!=r-l+) fail=;
        return;
    }

    int m=(l+r)/;
    if(L<=m) quary2(L,R,l,m,*rt);
    if(fail) return;
    if(R>m) quary2(L,R,m+,r,*rt+);
    if(fail) return;
}

int main()
{
//    freopen("in.txt","r",stdin);
    while(~scanf("%d%d",&N,&Q))
    {
        while(!S.empty()) S.pop();

        build(,N,);
        for(int i=;i<=N;i++) flag[i]=;

        for(int i=;i<=Q;i++)
        {
            scanf("%s",op);
            if(op[]=='D')
            {
                scanf("%d",&num);
                S.push(num);
                flag[num]=;
                update(,num,,N,);
            }
            else if(op[]=='Q')
            {
                scanf("%d",&num);
                if(!flag[num]) printf("%d\n",);
                else
                {
                    ans1=,ans2=;
                    fail=;
                    if(num->=) quary1(,num-,,N,);
                    fail=;
                    if(num+<=N) quary2(num+,N,,N,);

                    int ans=ans1+ans2+;

                    printf("%d\n",ans);
                }
            }
            else if(op[]=='R')
            {
                if(S.empty()) continue;
                num=S.top();
                S.pop();
                flag[num]=;
                update(,num,,N,);
            }
        }
    }
    return ;
}