HDU_5372 树状数组 （2015多校第7场1004）

比赛的时候没做出来，看了题解发现，没有正确理解一个条件，每次插入线段的长度是递增的！！！也就是不可能出现横跨要查询区间的情况。那么记录<=查询区间的右端点的线段数，减去<查询区间的左端点的线段数，就是答案了，初始化的时候做一次离散化。

#include <cstdio>
#include <cmath>
#include <algorithm>
#include <cstring>
#include <queue>
#include <stack>
#include <map>
#define ll long long
#define FOR(i,x,y)  for(int i = x;i < y;i ++)
#define IFOR(i,x,y) for(int i = x;i > y;i --)
#define N 220000

using namespace std;

struct Commends{
    int l,r;
    int type;
}cmd[N];

int n,cnt,num[N<<1],l[N],r[N],m;
map <int,int> mat;

int lowbit(int x)   {return (x&(-x));}

int C1[N<<1],C2[N<<1];

void Modify_1(int x,int val){
    while(x <= n){
        C1[x] += val;
        x += lowbit(x);
    }
}

void Modify_2(int x,int val){
    while(x <= n){
        C2[x] += val;
        x += lowbit(x);
    }
}

int GetSum_1(int x){
    int sum = 0;
    while(x > 0){
        sum += C1[x];
        x -= lowbit(x);
    }
    return sum;
}

int GetSum_2(int x){
    int sum = 0;
    while(x > 0){
        sum += C2[x];
        x -= lowbit(x);
    }
    return sum;
}

int Query(int u,int v){
    int t2 = GetSum_2(v);
    int t1 = GetSum_1(u-1);
    return t2-t1;
}

int main(){
    //freopen("test.in","r",stdin);
    int tCase = 0;
    while(~scanf("%d",&m)){
        printf("Case #%d:
",++tCase);
        int v,b;
        n = cnt = 0;
        FOR(i,0,m){
            scanf("%d%d",&v,&b);
            cmd[i].type = v;
            if(!v){
                n ++;
                num[cnt++] = b;
                num[cnt++] = b+n;
                cmd[i].l = b;
                cmd[i].r = b+n;
                l[n] = b;
                r[n] = b+n;
            }
            else{
                cmd[i].l = l[b];
                cmd[i].r = r[b];
            }
        }
        n = 0;
        sort(num,num+cnt);
        mat[num[0]] = ++n;
        FOR(i,1,cnt){
            if(num[i] != num[i-1])
                mat[num[i]] = ++n;
        }
        memset(C1,0,sizeof(C1));
        memset(C2,0,sizeof(C2));
        FOR(i,0,m){
            if(!cmd[i].type){
                printf("%d
",Query(mat[cmd[i].l],mat[cmd[i].r]));
                Modify_1(mat[cmd[i].l],1);
                Modify_2(mat[cmd[i].r],1);
            }
            else{
                Modify_1(mat[cmd[i].l],-1);
                Modify_2(mat[cmd[i].r],-1);
            }
        }
    }
    return 0;
}

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