Hdu 5372 Segment Game (树状数组)

#include <map>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;

const int maxn = 200005;
typedef long long LL;
struct opera
{
int a, l, r;
}p[maxn];
int cl[maxn], cr[maxn], al[maxn], ar[maxn], L[maxn];
//树状数组不能从0开始
int lowbit (int x)
{
return x & (-x);
}

int sum (int x, int a[])
{
int Sum = 0;
while (x > 0)
{
Sum += a[x];
x -= lowbit(x);
}
return Sum;
}

void change (int i, int x, int a[], int n)
{
while (i <= n)
{
a[i] += x;
i += lowbit(i);
}
}

int main ()
{
int n, m, cnt, t, cas = 0;
while (scanf ("%d", &t) != EOF)
{
memset (cl, 0, sizeof(cl));
memset (cr, 0, sizeof(cr));
n = m = cnt = 0;

for (int i=0; i<t; i++)
{
scanf ("%d %d", &p[i].a, &p[i].l);
if (p[i].a == 0)
{
cnt ++;
p[i].r = p[i].l + cnt;
al[n++] = p[i].l;
ar[m++] = p[i].r;
L[cnt] = p[i].l;
}
}

sort (al, al+n);
n = unique (al, al+n) - al;
sort (ar, ar+m);
m = unique (ar, ar+m) - ar;
map <int, int> ml, mr;

for (int i=0; i<n; i++)
ml[al[i]] = i + 1;
for (int i=0; i<m; i++)
mr[ar[i]] = i + 1;

cnt = 0;
printf ("Case #%d:\n", ++cas);
for (int i=0; i<t; i++)
{
if (p[i].a)
{

int left = ml[L[p[i].l]];
int right = mr[L[p[i].l]+p[i].l];
change (left, -1, cl, n);
change (right, -1, cr, m);
}
else
{
int ansl = sum (ml[p[i].l]-1, cl);
int ansr = sum (mr[p[i].r], cr);
printf ("%d\n", ansr - ansl);
change (ml[p[i].l], 1, cl, n);
change (mr[p[i].r], 1, cr, m);
}
}
}
return 0;
}