PKU 2352 - Stars (树状数组)
题意
统计每个level的星星个数。每个星星的level是X、Y坐标都比他小的星星个数。
思路
这题的坐标都帮我们排序好了,直接用树状数组统计x即可。
代码
#include <cstdio>
#include <stack>
#include <set>
#include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <functional>
#include <cstring>
#include <algorithm>
#include <cctype>
#include <string>
#include <map>
#include <cmath>
#define LL long long
#define SZ(x) (int)x.size()
#define Lowbit(x) ((x) & (-x))
#define MP(a, b) make_pair(a, b)
#define MS(arr, num) memset(arr, num, sizeof(arr))
#define PB push_back
#define F first
#define S second
#define ROP freopen("input.txt", "r", stdin);
#define MID(a, b) (a + ((b - a) >> 1))
#define LC rt << 1, l, mid
#define RC rt << 1|1, mid + 1, r
#define LRT rt << 1
#define RRT rt << 1|1
#define BitCount(x) __builtin_popcount(x)
const double PI = acos(-1.0);
const int INF = 0x3f3f3f3f;
using namespace std;
const int MAXN = 35000 + 10;
const int MOD = 1e9 + 7;
typedef pair<int, int> pii;
typedef vector<int>::iterator viti;
typedef vector<pii>::iterator vitii;
int C[MAXN], n, val[MAXN];
int Sum(int x)
{
int ret = 0;
while (x > 0)
{
ret += C[x];
x -= Lowbit(x);
}
return ret;
}
void Update (int x)
{
while (x < MAXN)
{
C[x]++;
x += Lowbit(x);
}
}
int main()
{
//ROP;
int i, j;
scanf("%d", &n);
for (i = 0; i < n; i++)
{
int x, y;
scanf("%d%d", &x, &y);
x++;
int ans = Sum(x);
val[ans]++;
Update(x);
}
for (i = 0; i < n; i++)
if (val[i]) printf("%d\n", val[i]);
else printf("0\n");
return 0;
}