POJ 2352 线段树＋树状数组
第一次用，用来学习
树状数组。。。
#include
<
cstdio
>
#include
<
cstdlib
>
#include
<
cstring
>
#define
MAX 32005
inline
int
lowbit(
int
n){
return
n
&
(
-
n);}
int
number[MAX
+
5
];
int
tree[MAX
+
5
];
int
sum(
int
n)
{
int
res
=
0
;
while
(n
>
0
)
{
res
+=
tree[n];
n
-=
lowbit(n);
}
return
res;
}
void
update(
int
n,
int
val)
{
while
(n
<
MAX)
{
tree[n]
+=
val;
n
+=
lowbit(n);
}
}
int
main()
{
freopen(
"
input.txt
"
,
"
r
"
,stdin);
int
n,x,y;
scanf(
"
%d
"
,
&
n);
for
(
int
i
=
0
;i
<
n;i
++
)
{
scanf(
"
%d%d
"
,
&
x,
&
y);
number[sum(x
+
1
)]
++
;
update(x
+
1
,
1
);
}
for
(
int
i
=
0
;i
<
n;i
++
) printf(
"
%d\n
"
,number[i]);
return
0
;
}
线段树
#include
<
cstdio
>
#include
<
cstring
>
#include
<
cstdlib
>
#define
MAX 32768
#define
START 0
typedef
struct
node
{
int
l,r;
int
val;
void
setnode(
int
a,
int
b)
{
l
=
a;r
=
b;
val
=
0
;
}
}node;
node stree[MAX
*
16
];
int
number[MAX
+
10
];
inline
int
left(
int
n){
return
2
*
n
+
1
;}
inline
int
right(
int
n){
return
2
*
n
+
2
;}
inline
int
mid(
int
a,
int
b){
return
(a
+
b)
/
2
;}
void
init(
int
pos,
int
l,
int
r)
{
stree[pos].setnode(l,r);
if
(l
<
r)
{
int
m
=
mid(l,r);
init(left(pos),l,m);
init(right(pos),m
+
1
,r);
}
}
int
query(
int
pos,
int
x)
{
if
(stree[pos].l
==
x
&&
stree[pos].r
==
x)
return
stree[pos].val;
int
m
=
mid(stree[pos].l,stree[pos].r);
if
(x
<=
m)
return
query(left(pos),x)
+
stree[pos].val;
else
return
query(right(pos),x)
+
stree[pos].val;
}
void
ins(
int
pos,
int
l,
int
r,
int
val)
{
if
(stree[pos].l
==
l
&&
stree[pos].r
==
r) stree[pos].val
+=
val;
else
{
int
m
=
mid(stree[pos].l,stree[pos].r);
if
(r
<=
m) ins(left(pos),l,r,val);
else
if
(l
>
m) ins(right(pos),l,r,val);
else
{
ins(left(pos),l,m,val);
ins(right(pos),m
+
1
,r,val);
}
}
}
int
main()
{
freopen(
"
input.txt
"
,
"
r
"
,stdin);
int
n,x,y;
init(START,
0
,MAX);
scanf(
"
%d
"
,
&
n);
for
(
int
i
=
0
;i
<
n;i
++
)
{
scanf(
"
%d%d
"
,
&
x,
&
y);
number[query(START,x
+
1
)]
++
;
ins(START,x
+
1
,MAX,
1
);
}
for
(
int
i
=
0
;i
<
n;i
++
) printf(
"
%d\n
"
,number[i]);
return
0
;
}